History and Origins
“These instruments are about more than just science. They are about exploration and discovery. When I look through a 200 year-old telescope, I don’t see cars on a distant highway, I see the captain of a storm-tossed clipper ship looking back – perhaps through an identical telescope.” ~ Terri Haag
This short version of our soon-to-be-released Reference Guide is provided as an historical reference to antique instruments of science and technology. It contains historical information for anyone conducting research for a school project or for personal interest. The History & Origins section is subdivided into the same categories as the rest of the website. It is linked to the Museum and the Catalogue-Museum Shop, categorically. Thus, while perusing the museum, you can quickly link to your relevant category of interest by clicking on the side bar and likewise from the Catalogue-Museum Shop. And you can easily link back again if you wish to resume your previous path. We hope you find our History & Origins section an interesting and useful resource.
ANTIQUE INSTRUMENTS OF SCIENCE, TECHNOLOGY & DISCOVERY
By David Moore Spatz, PhD
(Excerpts from Opticalia-Antiques’ Reference Guide to Antique Instruments of Science, Technology & Discovery, available from this website from late-2010.
Historical Overview
Scientific instruments are the tools used by scientists, explorers, surveyors, engineers and navigators in the exploration, discovery, study and analysis of the world around us. Instruments of antiquity were used to discover, observe and document a wide range of natural phenomena. Science and technology have always progressed in parallel. These two disciplines are inextricably bound in a relationship of mutual dependence.
In the overall scheme of social and cultural development, science and technology are still in the cradle. To get a feeling for just how young the discipline of science is, one need only be aware that the word ‘scientist’ was first coined in the English language around 1832. Fully half of all noteworthy inventions and developments in science and technology since the earliest stone tools were fashioned 2.5 million years ago have occurred over the past 150 years, or to see it another way, in 1/17,000ths of that time period.
Instruments of Antiquity
Much of what we know about the earliest scientific instruments comes from artifacts discovered in Egyptian, Babylonian, Chinese, Greek and Roman ruins. They include scales for weighing, rules and dividers for drawing, graduated vessels for measuring, staffs and sighting tools for surveying, rough magnifying lenses, sundials and rain gauges.
Drawings of scales date to 3000 BCE Egypt and parts of a balance were found in Egyptian ruins dating to 1450 BCE. The earliest known map, which is of a gold mine, drawn on papyrus, is from 1320 BCE Egypt. Meridian instruments that determine the due south position of planetary bodies were in use in Babylon around 1250 BCE. One might claim that the massive stone circle at Stonehenge, the first phase construction of which began around 2800 BCE to track movements of heavenly bodies, is an astronomical instrument on a grand scale.
Later in the millennium, around the sixth century BCE, an energetic and industrious Greek named Theodorus of Samos is credited with inventing a wood lathe, bubble level, carpenter’s square and locks and keys. An asbestos wick spirit lamp appeared in China about this time. By the second century BCE, the Chinese were making compasses by suspending a thin sliver of lodestone from a string. Asian counting rods date to the same period.
A man, who we might credit as the father of scientific instruments, Claudius Ptolemy, described an astrolaban, the original armillary sphere, and a large quadrant, called a ‘plinth’ used to measure the height of the sun, in his book Almagest, published around 145 CE Ptolemy also used celestial globes and drew a world map. The astrolabe, the quintessential scientific instrument, along with the quadrant, and successor to the ancient armillary sphere and celestial globe, is believed to have been invented during the third century CE. The oldest known surviving astrolabe is from about 830 CE Baghdad, and between the tenth and thirteenth centuries, exquisitely engraved examples were produced in the mid-east.
The following centuries are known as the Dark Ages in Europe. And for good reason, too. Nothing happened. All progress during this hiatus of human imagination and creativity in the western world was restricted to the far east where the Chinese improved printing, mining, metallurgy, guns and clocks. It wasn’t until the 1300s that mechanical clocks were introduced into Europe when trade with the east was in its incipient stages.
1400s The Renaissance: Curiosity Stirred
At the beginning of the 1400s and during the early Renaissance, ship captains found more pressing needs to improve the navigational instruments they used to determine position at sea and to map new lands. These urgent practical concerns began to stimulate scientific investigation and innovation in the west for the first time. The freedom to do so was motivated by the lure of trade, profit and the acquisition of gold. So it was with the blessing of both regal and papal authority, without which the explorers never would have left port. Necessity became the mother of invention. This was known as the Age of Exploration. And for science it might be called the Age of Printing.
One of the most extraordinary events happened about mid-century that would change the world forever and touch every field of science to come – invention of interchangeable metal type printing. Gutenberg’s ‘moveable type’ presses and foundry technique for mass production of metal type revolutionized information transfer, putting the previously astonishingly expensive book and other papers in the hands of the average person. Most developed countries of the time had Gutenberg moveable type printing presses by 1500, which greatly improved communication, sharing of knowledge and dissemination of new discoveries. For the first time in history learning could be self-directed instead of controlled by the learned authority.
The quadrant and the astrolabe were essential tools of navigators at this time and instructions on how to construct and use an astrolabe to locate one’s position relative to a star was published late in the 1300s. The navigational astrolabe evolved into a lighter open framed metal wheel easier to hold vertically in strong winds. It was simpler in design intended to provide the angular distances of the sun and other celestial bodies. New, improved star maps and tables were published by Ulugh Beg, and in 1484, King John III of Portugal appointed a commission of mathematicians to refine methods of determining latitude at sea.
Magnifying eyeglasses had been around as aids for people with farsightedness since the 1300s. Then around 1450, Nicholas Krebs invented spectacles for nearsightedness to bring distant objects into focus. These optical developments would eventually lead to revolutionary inventions almost two centuries later.
Leonardo da Vinci accomplished most of the work for which he is famous in the last decade of the century, drawing flying machines, conceiving a pendulum clock, construction rolling mills and discovering capillary action, among other things. And it was in 1492, that Christopher Columbus on his way to China stumbled on the Americas, beginning the conquest of the other half of the world, to that time unknown or at least unrecorded, and yet unexploited that would consume much of the energies of the western world for centuries to come.
1500s The Reformation: Freedom to Move
The 1500s can perhaps best be described as a revival of free-thinking and a stage-setting period for the grand play of scientific discovery and innovation that was to open a century later. The Renaissance was still in full swing at the early part of the century, and inquisitive minds were beginning to observe, question and investigate virtually everything. The church was finally getting out of science's way, and though subtle and slow, modification to the ancient ‘wisdom’ of the past was becoming more accepted, though not yet so widely encouraged. Printing was ubiquitous by now and books proliferated until anyone who wanted one could carry it proudly as a status symbol even if they couldn’t read. It was kind of like having a cell phone without talk time. For science the 1500s might be called the Age of Geography and Surveying.
There was little specialization during the 1500s and great thinkers like Leonardo da Vinci at the opening of the century were combining art, architecture, math, engineering and science in one comprehensive process of study, experimentation and prophecy. Copernicus, after prolonged and tedious observations and calculations by hand established that the sun is the center of the solar system, not the earth, a discovery that remained opposed by the church and controversial with scientists until confirmed by Galileo late in the century. Tycho Brahe added to Copernican theory by observing a comet pass through the solar system undisturbed disproving the Aristotelian model of layers of crystal spheres.
The mariner’s astrolabe was replaced with the Jacob’s staff or cross staff early in the century. In 1569 Gerardus Mercator reintroduced a flat map projection first used by the Chinese around 940 to improve course plotting and mapping of coastlines on the curved surface of the Earth. Geography was prominent during the century and cartographers produced many new maps and earth globes. The ship’s log for tracking speed was first developed.
The sector, progenitor of the slide rule and all calculating devices to follow, is believed to have been invented by a colleague of Galileo around 1568 and enhanced and improved by Galileo himself around 1598. The abacus was first described at the end of the century about the time John Napier discovered logarithms which would lead to invention of the slide rule in the first half of the next century.
The first theodolite, one with a sighting alidade, since telescopes had not yet appeared, was invented by Leonardo Digges. Similar surveying instruments like the circumferemeter and graphometer were also developed during the century. The pin-hole camera or camera obscura destined to become the first camera housing for film 250 years later was invented by Giamattista della Porta around 1570.
1600s Age of Reason: The Scientist’s Tool Kit is Born
Serious, unrestrained, scientific inquiry, that began during the 1500s, lead to invention of a variety of scientific instruments of monumental importance in the 1600s. Application of these new inventions to observation and empirical documentation would move human interaction with nature from one of speculation and theory to one of experimentation, application and discovery. For scientific instrument this might be called the Age of the Scientist’s Tool Kit.
There were at least seven inventions during the 1600s that were key to the advancement of science and the inventions to come. They were the telescope, compound microscope, thermometer, barometer, pendulum clock, slide rule, and air pump. And just as important two other developments would add to the scientist’s tool kit in extraordinary ways – the discovery of calculus and analytical geometry and the development the scientific method of investigation.
The pendulum clock, patented by Christiaan Huygens in 1657, greatly improved the measurement of small intervals of time, a critical parameter basic to scientific investigation. Galileo had worked with pendulums to tick away the time, but Huygens succeeded by altering the normal pendulum in a way that makes it oscillate more rhythmically.
The barometer, invented by a pupil of Galileo, Evengelista Torricelli, and one of Torricelli’s colleagues, allowed measurement of air pressure; and the air pump, invented in the mid-1600s by Otto von Guericke, enabled scientists to study the properties of air in a systematic and controlled manner for the first time. The thermometer, known to have been used in chemical labs by 1610, was likely invented by Galileo based on his work at the end of the 1500s with a thermoscope, or air thermometer.
Galileo also constructed the first known telescope, writing an account in 1610 that he had delved into the theory of refracted light (bending light waves) and constructed a refracting ‘telescope’, ultimately creating one that magnified to a power of over 30. The reflecting telescope, which uses mirrors to gather light and reflect it to the eyepiece was invented by James Gregory in 1663. It was modified a few years later by Isaac Newton to a design that still bears Newton’s name.
The microscope was invented about the same time as the telescope in the early 1600s, possibly earlier and probably in Holland. The earliest microscopes were of the ‘simple’ type, using a single lens held close to the eye but they could magnify up to 100x. The first compound microscope described was one constructed for Robert Hooke, who published a description of the instrument and described its use in Micrographia in 1665.
Mathematics took bold strides during the century. Invention of the slide rule, originally a circular disc, is attributed to William Oughtred about 1630. He was reluctant to publish his designs because he thought the slide rule would make students lazy and unable to do math by hand. Both Isaac Newton and Gottfried Leibniz independently discovered calculus in the 1660s, which allowed sophisticated mathematical investigation of motion and continual change. Leibniz also invented a small mechanical calculator with knobs, handles and gears, a device that continued, in slightly varying form, to be produced for over 300 years.
Technological advance at this time was paralleled by theoretical and philosophical considerations, which lead to acknowledgement of what is now known as the ‘scientific method’. Men like Francis Bacon and Rene Descartes stressed the importance of austere deductive reasoning and systematic experimentation to build up objective empirical evidence on which to base theory and further testing.
1700s Age of Enlightenment: Taking Scientific Instruments Seriously
As the instruments invented during the 1600s were developed and became increasingly available, scientists of the 1700s made many noteworthy discoveries. This was the age of the gentleman scientist. It was quite fashionable in Europe and America for nobility and men of social distinction to have collections of natural specimens. Even progressive ladies of the time might have a microscope on their parlour table. For scientific instruments this might be called the Age of Refinement.
During the 1700s advances in engineering technology and metallurgy began to impact the design and manufacture of scientific instruments. For example, invention of the dividing engine (mechanical means of marking divisions on scales) by Jesse Ramsden occurred in 1774, the turning lathe around 1778, metal rolling mills by 1786 and the slide rest lathe in 1797. Electromagnetic phenomena peaked the interest of scientists during the century, leading to invention of the torsion balance and electroscope.
John Dolland, a London based instrument designer and prolific manufacturer, refuted a previously unchallenged but erroneous conclusion of Isaac Newton that chromatic aberration in lenses could not be overcome. Dolland used flint glass (lead glass) as a refractive medium and corrected for color image distortion in 1757.
The octant or Hadley’s quadrant was invented in 1730 and replaced the cross-staff and back-staff for navigation, followed by development of the sextant in the 1770s. The sextant with its superior accuracy allowed the user to better estimate longitude at sea based on the ‘lunar distance’ method (distance of some stars from the moon) that was discovered in 1767. Determination of longitude by reference to a port time was becoming so important for navigation at sea that the British government offered 20,000 pounds to anyone who could develop a reliable ocean-worthy clock or chronometer accurate to within 3 seconds per day. Although many important men of letters and prestige competed, the prize was finally awarded in 1773 to John Harrison, an innovative watch and clock technician and inventor. Chronometers were carried aboard most ships by the end of the century.
By the end of the century production and distribution of scientific instruments had entered a new era. Shops that had been characterized by a single craftsman at the start of the century were being replaced by large shops with many workers at the end of the century.
1800s Age of Progress: Scientific Instruments Proliferate
Historians note that the process of instrument development and manufacture changed markedly during the 1800s, not only to larger shops with many workers but also from an enterprise characterized by single individuals who were both scientists and instrument makers to the separation of the scientist from the manufacturer. This was also The Age of Electricity.
Alessandro Volta lead what would eventually end up as a century of marvellous innovation, by inventing the battery in 1800. Then during the second half of the 1800s with a watershed send-off by London’s Great Exhibition of 1851, which showcased impressive new inventions, renewed curiosity in science and an emergent generation of entrepreneurs led the way to spectacular creativity that would become known as the ‘Age of Progress’.
Important inventions of the century include the blowpipe, which became an indispensable tool of chemistry by 1820 and was labelled the ‘chemist’s stethoscope’. Steam engines, which were common in the early part of the century, had been largely supplanted by electric motors and gasoline engines by the end of the century. Spherical aberration was corrected in lenses in 1830 and by the 1850s the microscope had finally entered a phase of serious application that has never ended. The first prismatic binocular, called ‘The Feldstecher’ was offered to the public by Zeiss in 1894.
At mid-century the barometer was revolutionized by the ‘aneroid’. Surveying instruments, including transit theodolites and field compasses proliferated by the end of the century due to increasing demand for detailed maps. Cameras, clad in wood cases, were recording images on metal sheets by mid-century, and the first crude movies were produced in the 1890s.
One of the greatest achievements during the 1800s was in electricity and electrical power generation. Incandescent electric lighting was introduced in the 1880s with Thomas Edison and Joseph Swan’s carbon filament bulb. Harnessing of electricity spawned experimental grid distribution of electrical power to households and businesses, and a new set of instruments for detecting and measuring electrical properties, like voltmeters, ammeters and ohmmeters were developed.
The revolutionary telegraph, invented in 1833 was overshadowed in 1876 when Alexander Graham Bell transmitted the first telephone message and in 1894 when Guglielmo Marconi began experimenting with radio technology. Revelations in the field of aerodynamics was beginning to excite the imagination of bold, adventurous men who would eventually invent and fly airplanes. The first automobile (three wheels) was designed by Karl Benz in 1885 based on development of the gasoline engine by Nikolaus Otto in 1877. These inventions and the businesses and industries that grew from them would lay the groundwork for a massive technological explosion during the twentieth century.
1900s Age of the Future: Technology Blossoms
Scientific instruments produced during the first quarter of the 1900s are at the threshold of what we generally define as antique (100 years old). But what we collect and deem valuable can be quite recent indeed, partly because the rapid innovation that has continued throughout the 1900s has lead to obsolescence in relatively short time intervals. For this reason, depending on rarity and condition, devices like telephones, cameras, and electrical instruments from the 30s and 40s; slide rules and calculating machines produced as late as 1970; desktop computers from 1980; GPS receivers from 1990; and many other relatively recent products may not be just ‘second hand’ but have the added value of being collectable.
People awoke in 1900 to what was to become an incredibly dynamic period of discovery, innovation and change that would transform lifestyles, businesses, economics, politics and science alike. And it was underway almost day-one with the first wireless transmission of radio waves that reached Guglielmo Marconi from across the Atlantic ocean in 1901. Electronics and the new internal combustion engine would play major roles in progress throughout the century. This was the Age of the Computer.
The year was 1903: The Wright Brother’s flyer lifted off for the first time at Kitty Hawk; the first truly commercial film, The Great Train Robbery, was released by the Edison Co; the Model A Ford was launched; and the first Harley-Davidson motorcycle was produced.
Albert Einstein published four revolutionary papers in physics in 1905, building later on his famous theory of relativity. The Sputnik satellite was launched by Russia in 1957, and in 1969 American astronauts walked on the moon. Incredible advances occurred in medicine, including, discovery of penicillin, development of a vaccine for polio, heart and kidney transplants, arthroscopy surgery, simple laser procedures to correct eye sight, artificial heart and joint replacements and cloning.
The first earth observation satellite, TIROS, was launched in 1960 and soon weather maps from space were being broadcast into every home with a television. Surveying and navigation were revolutionized by Geo-Positioning System (GPS) satellites, which became fully operational in 1995. And by the end of the century laptop computers were in most briefcases and many backpacks; digital cameras had begun to dominate the photographic scene; and cell phones the size of a pack of cigarettes were as common as purses.
What would Galileo think should he revisit earth today? I imagine he would be astonished but perhaps not so surprised with discoveries of distant nebulae viewed so brilliantly with highly sophisticated instruments like the Hubble Space Telescope. He might be awestruck, though, to learn that this advanced instrument is onboard a man made satellite rocketed into orbit hundreds of miles above the earth to avoid atmospheric interference; is monitored and adjusted by computers with electronic telemetry from earth and other satellites; and is repaired by men and women called astronauts, from a space shuttle. I suspect he might be even be amazed that crystal clear, high resolution images from the Hubble telescope can be digitally transmitted via satellite communications net to astronomers scattered around the globe and to a worldwide press agency in a matter of minutes.
We can only imagine, what in the world the twenty-first century will bring!
Scales, Weights and Measures
To learn more about antique Scales, Weights and Measures order Opticalia-Antiques’ 500-page illustrated Reference Guide to Antique Instruments of Science, Technology and Discovery. For ordering info click*
Scales are among the oldest known scientific instruments. Ancient depictions of simple balances and weights dating to the third millennium BCE have been found at Egyptian sites. Scales are also depicted in books of death from Egyptian sarcophagi, on stone reliefs of the Hittites, on Greek pottery, and on frescos from Egyptian, Greek and Roman times. The oldest known physical example is an Egyptian balance dating to 1450 BCE. Balances were used in ancient China for trade and commerce and in Roman mints to weigh coins and are still made today.
Scales became increasingly important over time as governments began to issue coinage and as doctors and chemists began to dispense pharmaceutical products. Accuracy and precision in weights and standards, over the centuries, suffered, and interestingly, in medieval times private citizens in some countries were prohibited from owning scales, because some clever man got the idea to melt down overweight gold and silver coins and profit from the difference. Different types of scales include the simple balance, bismar, steelyard, self-indicating, spring, torsion and precision laboratory among others. Coin, gold and diamond scales may be labeled as such if the weights are calibrated to grams, carats or metal currency.
The earliest and most common type of scale is the balance, which consists simply of two pans (originally called ‘scales’) suspended from a beam. The Steelyard and bismar are balances with one beam arm longer than the other. The bismar scale uses a fixed weight or counterpoise at one end of the beam with the object or material to be weighed hung by a hook from the other. Steelyard scales have a fixed fulcrum and a beam that acts like a lever. Specialized Coin scales are commonly steelyard in design with grooves or notches along the beam to set the counterpoise for quick comparison to test the weight of a coin with a standard.
Precision Laboratory scales were first described in 1798 and became widely available around 1830. They are basically balances with delicate, sensitive mechanisms to increase precision. From the mid-1800s they were usually enclosed in glass paneled hardwood cases with sliding or hinged front or side doors for easy access and included a drawer for weights, tweezers and other accessories. Pans on precision scales are usually brass or nickel brass and can be quite small. The balance beams usually have a fixed or separate link with a small, sharp brass ridge hanging at the bottom. The wire loops that hold the pans have a separate link called an ‘agate box’, which contains a small bar of agate carved with a groove to fit delicately over the brass ridge. The ‘rider system’, which appeared around 1850, is an overhead beam equipped with wires and hooks to add minute amounts of weight for high-precision measurements. ‘Single pan balances’ introduced in 1947 speeded up weighing through a system of hand operated cams that lowered or raised weights. Micro-balances, that operate with a quartz string which twists proportionally to the weight, were described in 1956, and electronic balances soon rendered mechanical chemical balances largely obsolete. There are many specialized laboratory scales designed to weigh specific objects. Some of these are in the Opticalia Museum.
Scales that are either high precision or sensitive to the slightest weight change are characteristic of diamond and gold scales. Portable gold and diamond scales, that dismantle to fit in small wood boxes, suitable for a coat pocket, were produced from the mid-1800s into the 20th Century. Made of brass or nickel brass, a simple balance is typical of these scales. The beam rests in a brass frame with a fixed pointer and a vertical bar for holding or hanging by cord. Alternatively the beam is positioned on a post that comes with the set. The post may screw into the top of the box. The pans are then hung by a thin cord to the ends of the beams by means of small hooks or agate boxes. Meant for travel, these scale boxes typically contained gram weights to weigh gold and carat weights to weigh diamonds. Larger desk top variety scales for diamonds and precious metals were also designed to dismantle and fit inside a mahogany or other hardwood box drawer. Precision laboratory scales, specialized for diamonds and gold, have small, sometimes tiny pans. Coin scales, in contrast, are commonly steelyard in design with grooves or notches along the beam to set the counterpoise for quick comparison of a coin with a standard. Early money scales had graduated beams made of ivory or wood that fit in a grooved flat wood box along with the counterpoise weight for easy transportation.
Floor and counter scales, too, are mostly balance beam in design, but with large pans to weigh large items or large quantities; however, the steelyard design is common in large floor scales intended for heavy products. One reason is its simple, hardy design and durability with few interconnecting parts. The steelyard scale consists of a graduated beam (usually in pounds, kilograms, ounces or grams) secured at one end – the fulcrum – with the weighing pan extended from the other end. A counterpoise weight is then slid across the beam to find equilibrium where the weight of the object is then indicated on the beam. Floor scales are commonly 3 to 4 feet tall with pans up to a foot across. Some Victorian floor scales are high ornate, usually made of wrought iron with brass pans. The English sovereign scale is a floor scale typically made of brass and nickel brass. It uses up to 500-sovereign equivalent weights to weigh coinage. Counter scales usually have short fulcrums, so sit low on the counter. Some are housed in wood or have metal skirts to hide the workings. They are commonly decorative with wood inlay or ornate metal designs. The micrometer scale by the Dodge Co. is a counter top scale that operates by torque. A large screw passes under the apparatus through a calibrated, graduated, geared wheel that turns in coordination with the screw to indicate weight when balance is achieve.
Postal scales came into use in the early 1800s and by mid-century had proliferated due to the introduction of pre-paid stamps and the need for letter scales. They come in many different styles and shapes and some are ornately designed, but most are simple balances and pans on a frame mounted to a wood platform. They are usually made of brass or nickel brass. The wood base invariably has recesses to accommodate round wafer weights, which are often nested or stacked, or, less commonly, rectangular weights. If metal, a small ring may be attached to the base in which the weights are stacked. Postal scales can be plain or works of art with inlay designs in the pans and ornate frames or have a creative design in the platform. Some postal scales are self-indicating. One type of self-indicting scale is believed to have been invented by Leonardo da Vinci around 1500. It consists of one pan or hook with a rotating dial and indicator needle. When suspended, the dial rotates up or down with the weight of the load or sample, and the indicator needle remains vertical to indicate weight. The Depose counterpoise scale, also manufactured by other firms, is fitted with a weighted pendulum that moves along a graduated arc, or alternatively the arc scale moves beside the pendulum indicator when weight is loaded. Spring loaded postal scales of various types largely superseded scales with weights by the 1950s, at least in 1st world countries, which in turn were largely replaced by electronic scales during the 1970s. Self-indicating scales are relatively inexpensive compared to electronic scales and still available.
Scales are used to weigh either in absolute quantities like ounces, grams, scruples, drams, drachmas, grains, pennyweights, carats, currency, or other unit of measure. Weights are typically inscribed or cast in relief to indicate their mass or to compare the weight of two objects. From 1400, with the exception of large weights to measure heavy items or heavy quantities of some product, the majority of weights used with scales have been made of brass. Weights come in many different shapes, including those of people and animals, but they are more commonly fashioned in geometric shapes like truncated spheres, ellipsoids, cylinders (drum weights), discs, pyramids, cubes, hexagons, octagons, cupcakes, bells and rectangular wafers to mention some. Sets of round flat brass weights usually nest within one another’rims from heaviest to lightest. Nuremberg-type weights are nested metal cups in a cup shaped container that was often elaborately decorated in the 1600s and 1700s. The outer cup has a hinged top with a fastener and the cup itself is a precisely gauged weight. They were still advertised by distributors into the twentieth century. Very large weights will likely have a handle to hold and most cylindrical and round weights have a mushroom shaped knob or ring on top to lift by hand. . Up to a point, the weights available control precision and that depends on a scale’s purpose. For example, a postal scale may only need to be accurate to within half an ounce, whereas a diamond scale needs 1000 times that precision.
The volumes of liquids and solid objects have been measured in a variety of different kinds of vessels categorically called volumetric measures. Cups, pitchers, vials, test tubes, cans, barrels, tanks, and baskets have been used as standards of volume. Most are graduated with a level scale for incremental volumes, but some are a simple single gauge of volume when ‘topped-off’. Fluid volumetric measures are one of the chemist’s and laboratory researcher’s basic tools.
Many containers are graduated for volume or capacity measures in fluid ounces, grams, grains, pints, cubic cm, fluid drachms and other units of measure. Some volumetric vessels were furnished in sets of graduated cups, goblets or pitchers. Containers are most commonly made of glass but depending on age may be brass, nickel silver, copper, ceramic, porcelain, fireclay, pewter, quartz glass, fused silica, enamelled steel, and after 1915, stainless.
Length standards originated with the dimensions of human body parts. For example an inch was the width of a man’s thumb when pressed down and a foot the length of that appendage that dangles from the end of your leg. Could you imagine, though, if my wife and I went about building us a house with both of us using our foot as a standard of measure. She wears a size 5 (U.S.) and I wear a size 12! There would not be one symmetrical, straight or level surface in the place. In practice, to obtain the foot standard, it was recommended to average by having a dozen or more men line up their foot, toe to heal. It became common to average the feet of 16 men, which became a standard in its own right – the rod – 16 feet. Also 12 thumb widths were used by some to measure a foot. A cubit is the length of a man’s arm from elbow to fingertips. The distance covered by a man holding both arms out straight is a fathom (6 feet). The length of a mile comes from the distance covered in 1000 paces (two steps), again presumably by some influential person who ‘set the pace’ or by taking an average.
The first permanent official standard of length, commissioned by King Henry VII in 1497, is an octagonal bronze rod one yard long, which is still in existence. Another common standard was the ell, which measures 45 inches and was used in the cloth trade. These standards were usually made of boxwood, mahogany or pine with brass caps and inlay. Yardsticks were sometimes made of brass and in the 1800s nickel brass. By the early 1900s steel was the more common medium.
Competition among manufacturers was for the most stable steel with the smallest coefficient of expansion so that by the very early 1900s metallurgical advances produced steels whose coefficients of expansion are negligible for surveying. There are 3 types of length scales – standard scale gauge, inside scale gauge and outside scale gauge. By 1910, these were being combined into one instrument called a triple standard. It has moveable sliding ends that extend like calliper claws to provide inside gauge on one side of the rule and an outside gauge on the other. Standard scales are either yard, 2-foot, 1-foot or meter gauges that come in mahogany boxes. With GPS and electronic distance measuring devises (DME), the old length measuring tools and techniques are in practice largely obsolete.
Surveying
To learn more about antique Surveying Instruments order Opticalia-Antiques’ 500-page illustrated Reference Guide to Antique Instruments of Science, Technology and Discovery. For ordering info click*
Any instrument used to plot a line on the ground, sight a straight line, record the geographical position of an object or landmark, outline a tract of land, measure a horizontal or vertical angle or find a horizontal plane can be categorized as a surveying instrument. Surveying instruments as we know them today have their roots in the ancient quadrant and the astrolabe, the latter believed to have been invented in the 3rd Century, CE Both were fixed with an alidade for measuring angles, another fundamental instrument in surveying. Alidades, as simple sighting devises, are among the oldest of scientific instruments. Surveying instruments overlap instruments used for navigation and astronomy.
The earliest surveying instruments known are from archaeological digs in the Tigris and Euphrates river valleys dating to 1000 BCE They consist of poles, ropes and sighting devises for rough surveying. The Greeks and Romans used a device called a groma, which was simply a staff mounted instrument consisting of crossed pivoting slats with open sites and a plumb bob. Narrow troughs of water have long been used to find horizontal. Made of wood or poor quality steel, instruments from that time period have rarely survived the ravages of climate, plunder, carelessness and indifference. If you want an authentic one for your collection, you may as well collect spores from outer space.
The circumferentor, developed in the early 1500s about the same time as the theodolite, has a horizontal circle graduated in 360° azimuth intervals. The instrument commonly incorporates a central compass and a rotating alidade. The similar graphometer,invented around 1598, consists of a semi-circle dial with two independently pivoting alidades bars. The instrument can measure vertical angles as well as horizontal depending on how it is held. Graphometers usually incorporate a magnetic compass. Because of its simple, compact and portable design, the graphometer was popular with surveyors for over two centuries, preferred over the theodolite by the majority well into the 1800s. The graphometer is smaller and handier than other instruments of its time and became the preferred surveying tool for over 300 years to the beginning of the 20th Century. These early surveying instruments were originally made of wood then brass.
Surveyor’s sextants, also called pocket sextants, were considered an essential tool of the surveyor by the mid-1800s. These portable sextants were very small - only 3 to 4 inches in diameter – and carried in leather cases. They can take angular readings in either vertical or horizontal planes and were used primarily in circumstances requiring trigonometry.
The earliest known written description of a theodolite is from 1512, but the earliest account of a theodolite, considered by many as the pre-eminent surveying instrument, being used in practical land surveying even though it took three hundred years to catch on, was designed into a practical tool for surveying around 1556, then forgotten well into the 17th Century. It is an altazimuth instrument, meaning it can measure angles in both the horizontal and vertical. It is made with a flat horizontal disk like the astrolabe that is divided into 360 degrees. They were designed both with and without a compass mounted in the middle of the horizontal dial. They are characterized by a circular or half circle plate or ring oriented vertically or at right angles to the horizontal dial and graduated over 90 degrees for measuring vertical angles. This two dimensional measuring capability is called altazimuth, the instrument more commonly called, ‘two-circle’. Theodolites developed into many different models, designs and sizes for specialized applications and diverse environments that can vary from high and airy mountain peaks to deep and cramped underground mines. For example, mine theodolites typically have either pivoting auxiliary telescopes mounted atop the vertical circle or the primary scope to allow sighting vertically up or down a shaft or winze or orient to nadir, or a hollow base axis so the surveyor can sight vertically down. In the early 1900s makers began enclosing the circles on theodolites (first the horizontal dial, then in time both the horizontal and vertical dials) for protection in the field and mines, and in the late 1920s added interior optics with protruding magnifying scopes to read the dials. One of the first theodolites of this type, the Tavistock, made by Cooke, Troughton & Simms is a double-reading (both circles can be read from the eyepiece through a magnifying tube) optical micrometer theodolite that went into production in 1930. Compact theodolites with a half-arc vertical dial that is breached at the top and bottom to create two arcs are called, ‘Mount Everest type’. Micrometer theodolites that allow greater precision became available early in the 1900s. Theodolites with optical distance measuring capabilities are called tacheometers. They were introduced around 1860, and early ones were based on slant distance differences or the distance between horizontal and vertical distances. They were typically sighted on graduated stadia staffs. Tacheometric stadia (cross-hairs) were placed in the eyepieces of precision levels around 1900. The gradioplane is a specialized theodolite that appeared about 1910. It has a normal horizontal dial and compass but in place of a vertical dial it sports a large helical ‘gradienter screw’ that allows measurement of very small vertical angles. Transit theodolites are designed with telescopes that swing in the vertical plane forward and backward 180 degrees in order to back sight.
Large levels intended for tripods differ from theodolites by lacking a vertical circle, half-circle or arc. From development of William Gravatt’s level in 1830 through the twentieth century, simple leveling telescopes with or without compasses have been called ‘dumpy levels’, referring to Gravatt’s design which had a high diameter to length ratio. They are designed both as simple leveling sights, commonly with a compass or azimuth dial, and as transit levels with a scope that can be rotated to back sight. The original transit level, invented in 1734, was called the ‘Y’ level, because the removable telescope rests on ‘y’ or ‘u’ shaped collars with a similar shaped hinged clip that swings and locks over the telescope to hold it in place. Thus the scope can be easily removed and placed to back site in the opposite direction. From the mid-late-1800s, most transits and transit levels manufactured have been designed with telescopes that swing in the vertical plane forward and backward to back-sight, just like a transiting theodolite; however, the ‘Y’ style was still being manufactured made into the early 1920s.
‘Alidade’ is both a principle of surveying as well as a material article. Alidades take various forms but can be as primitive as two sights mounted along a pole or string, or at opposite ends of an arc or ring. The sights on a rifle barrel might be considered alidades. Alidades facilitate sighting a straight line, lining up one’s position with a distant object and measuring horizontal and usually vertical angles as well. As a plane table alidade, they are attached to scaled parallel rules, placed over a map or chart on a table, typically a table atop a tripod, and used to survey or map a local site. The parallel rule provides the means to draw lines in parallel to the sight direction and to plot features to scale relative to a stationary position. Modern alidades are usually equipped with a telescope and vertical arc or internal inclinometer. Plane alidades with only sighting arms hinged to a ruler were made well into the twentieth century and still available. Today, the alidade principle of ancient times is incorporated into more sophisticated devises like electronic theodolites and the ‘total station’.
The surveyor’s compass, designed in the mid-1850s, is simply a large, 5 to 6-inch diameter compass in a brass case with hinged sighting alidades, spirit level and vernier scale. Some have interchangeable alidades and telescopes. It usually has a threaded base for mounting to a tripod or staff. Miner’s dials are similar except later models were more compact, fitted with smaller dials, the vertical dial mounted low against the horizontal dial and equipped with a short telescope sometimes mounted to a gimbaled frame that rotates to offer vertical sightings both up and down.
The first true rangefinder capable of being operated by a single user was patented in 1860 by Patrick Adie. It is based on parallax and consists of two telescopes that reflect images to a central eyepiece. The images are brought into coincidence by adjusting the angle of one reflector and the distance then read from a scale. A more advanced instrument called a coincidence rangefinder that uses moveable prisms was designed in 1888 and a stereographic type in 1893.
Small hand-held and staff-mount surveying instruments come in many forms for many purposes. They include such devices used both on and off staffs like the circumferentor and similar graphometer (described above), as well as surveyor’s sextant, rangefinders, pocket mining transits, hand and reflecting levels, rule clinometers, clinometers/compasses, and mountain barometers. Rule clinometers are elegantly fashioned multi-purpose instruments. They consist of a thick, hinged, boxwood foot rule in which an inclinometer with vernier scale is mounted at the hinge position. They incorporate a spirit level, retractable alidade sights and brass cased compasses, the latter either stationary or gimballed. The Abney level, invented in 1870 and called ‘The Miniature Theodolite’, became wildly popular among surveyors and engineers. It is a small hand held clinometer, consisting of a 4 to 6-inch long rectangular telescope on the side of which is mounted a semicircle arc, graduated in degrees for measuring vertical angles with a spirit level normally attached atop the arc and a small spirit level. While viewing through the telescope at any angle a mirror reflection of the spirit bubble can be viewed through a small window while the user rotates the arc to level, then notes the angle of inclination on the arc. Sighting and geological compasses are described in the Compass section. Some designs include a threaded recess for staff attachment and some, like the Brunton Compass, has a specially designed tripod clamp.
Surveying accessories include among many others, measuring chains and tapes, waywiser, cross-staff head, spirit level, artificial horizon, traverse tablet, stadia staff, surveyor’s slide rule and plumb bob or plummet. Crellin's Complete Traverse Table is a simple mechanical traverse marker that operates logarithmically. It consists of a brass tablet with a row of brass levers that can be rotated for counting through 1 to 10, 10 to 100, and 100 to 1000, mush like an abacus. Plumb bobs or plummets are quite varied and some large brass or nickel-brass plumb bobs quite elegant. Some come with a detachable end that screws off to give access to a spool with string that feeds out a hole to tie to a tripod, plane table or other devise for leveling. The first practical spirit level, which is a cylinder of glass filled with water or alcohol and encased in brass, was developed in the 1600s and was being mounted on surveying instruments by the early 1700s. The standard surveyor’s chain, developed by Aaron Rathborne around 1615, evolved over the centuries through tapes and made of metal, metal reinforced cloth, and durable plastic to electronic distance measuring devises used in the ‘total station’ today. The waywiser, a wheel for measuring distances along the ground, was first patented by Isaac Fenn in 1765. The surveyor’s cross-staff head is a cylindrical, rectangular or octagonal shaped devise with cross sight that mounts to the top of a pole and provides precise 90° sighting angles. Some have a compass mounted to the top and were popular into the 1900s and some were constructed with prisms to sight a turn either right or left.
Magnetic Compasses & Dials
To learn more about antique Compasses and Dials order Opticalia-Antiques’ 500-page illustrated Reference Guide to Antique Instruments of Science, Technology and Discovery. For ordering info click*
The magnetic compass The compass in its most fundamental form consists simply of a magnetic needle with a colored tip to indicate north, mounted on a pivot at the center of a compass card marked with the cardinal directions – N, S, E, W. Quadrants are normally subdivided, either by degrees or marked with lines to indicate NW, NE, SE, and SW. Wood-clad compasses are among the oldest designs The compass has been used in navigation, surveying, mapping, studies of rock magnetism, and investigations into electromagnetics. In its earliest and most simple form the compass dates to ancient China about the second century BCE when it was simply a suspended sliver of natural lodestone. By about the seventh century CE, the Chinese had developed a floating magnetized needle mounted to a piece of wood or reed. (magnetized by stroking soft iron with natural lodestone).
Sundials (dials) are known from at least 600 B.C. Egypt and China and 500 BCE Greece. There are over a dozen different, formally designated types of sundials but they are typically circular, oblong or rectangular in shape, made of wood, ivory, silver or brass and marked to indicate time. All are fitted with a gnomon or vertical shadow-casting protrusion, which, on some types, is simply a thin string. They were sized to either mount on a table or pedestal or carry in the pocket. Some are constructed to be oriented with the disk horizontal, others vertical and still others inclined. Compasses were fitted to sundials during the late 1200s CE and a great number were made during the 1600s and 1700s. They were used to adjust clocks and pocket watches as well as to tell time themselves. They continued to be popular as pocket watch size instruments for calibrating watches until the mid-1800s when the widespread and accurate clocks of telegraph companies made sundials largely obsolete.
The dipleidoscope, a sophisticated type of dial, was invented in 1843 by Edward Dent. By marking the meridian passage of the sun using a prism, compass and magnifying lens, the instrument determines time to within a few seconds of accuracy. The nocturnal is a related devise popularized in the early 1500s. It is used to find time at night with reference to the circumpolar stars. The nocturnal was used well into the 1700s and revived during the World Wars as a celluloid version called a ‘star clock’ as backup for military troops.
Sighting and geological compasses used by surveyors and geologists are usually fit with two sighting alidades, hinged so they can be turned down against the compass face when not in use. One alidade may be served by a sighting line or point on a hinged lid. These compasses are normally marked either in azimuth degrees – 0-360 – or in 90 degree quadrants with east and west reversed so the needle registers the direction of the pointer. The first recorded use of compasses in surveying was in the early 1500s when they were mounted first to astrolabes then circumferentors and graphometers. They remained a mainstay of surveying into the 20th Century. Geologic compasses are typically fitted with a vertical angle indicator (inclinometer). Older compasses had a needle loosely fixed at the center post along with the magnetic needle, so it would register the angle of inclination on a separate graduated arc when the edge of the compass was positioned against an incline. Later models have a small spirit bubble atop a small arc with an indicator needle below that registers inclination along a graduated arc when the bubble is centered. The prismatic compass was designed in 1812 and has a right angle magnifying prism attached to the back site with which to read fractions of a degree from the scale while holding the sights in steady alignment. Compasses have been made as wrist straps, mounted on walking cane handles and map chartometers, and made as watch swabs, brooches and pins.
Marching and traversing compasses are built on the same basic design as sighting and geologic compasses but without sighting alidades. Some have a normal compass needle, others a rotating compass card with a fixed azimuth dial around the periphery. Developed in the early 1900s, the compass case is commonly filled with fluid to dampen or slow down the otherwise erratic movement of the compass card that rests on a pivot with the magnetic needle attached either on top or bottom of the card. Compasses of this type are usually small and fitted with a hinged lid, sometimes with a ‘Hunter’ glass window.
Marine compasses are usually mounted in a protective housing like a wood box or a wood or brass dome called a binnacle. The first reference to gimbals on compasses for marine navigation was in 1537. The azimuth compass is a large marine compass used at sea to sight on the sun at sunup or at noon in order to determine magnetic deviation from true north. This application requires knowing the date and latitude, enabling the crew to calibrate the ship’s navigational compass to true north. The card of a mariner’s compass has 32 divisions called rhumb-lines instead of 360 degrees. Rhumb lines simplify navigational headings and tracking especially in high winds and rough waves.
A serious drawback to the magnetic compass for navigation at sea is the inherent wobble and oscillation of the needle. Any technique that stabilizes the needle is called ‘dampening’, and one of the earliest methods of dampening was the electromagnetic approach of placing the compass in a copper bowl. A liquid filled case, which became the preferred method of dampening, was patented in 1813.
The magnetic compass has been replaced for many navigational applications by the gyrocompass, which rotates on electrically driven wheels in order to maintain its position in space relative to magnetic north regardless of the orientation and motions of the vehicle in which it resides. Interestingly, Albert Einstein, a patent authority among his other credentials, was called as an expert witness to help settle a patent dispute in a court case involving a gyroscope in 1914.
Inexpensive, hand held Geo-Positioning System (GPS) receivers began replacing magnetic compasses in many applications during the 1990s. They serve as a compass for surveying and can be programmed to plot course bearings to any point, such as a rendezvous, base camp, parked vehicle or nearest pub.
Microscopes
To learn more about antique Microscopes order Opticalia-Antiques’ 500-page illustrated Reference Guide to Antique Instruments of Science, Technology and Discovery. For ordering info click*
The microscope is fundamentally like the telescope. They both use magnifying lenses mounted in a tube of some sort. The principle difference is the lenses of simple and compound microscope are smaller than those of a telescope and ground to give a short focal length for high magnification over a short distance. Historians are unsure exactly when and by whom the microscope was invented, but it is generally agreed the event took place about the same time as the invention of the telescope and probably in Holland, Italy or England. Galileo made the telescope an overnight sensation. That was not the case with the microscope. It took time to grow on us. One reason for this is the early proto-scientist’s fascination with the stars. William Smith, the geologist to map England and create ‘The Map that Changed the World’ said, if Newton had looked at the ground instead of the stars, perhaps geology would not have lagged so far behind.
The earliest microscopes are called simple microscopes or the ‘single’ type because they use a single lens. The lens is usually encased in metal, ivory, tortoise shell, horn or wood with a small handle. Lenses ground to 1/10-inch diameter can magnify up to 100x, and some early lenses were actually made of polished beads of glass. The first simple microscope ever known to be on display was in a London exhibition in 1619, and the earliest illustration known is Isaac Beeckman’s drawing of a ‘microscopium’ in 1631. The Leeuwenhoek microscope, one of the earliest simple microscopes and named after its inventor, Antoni van Leeuwenhoek, is a small rectangular plate made of brass or silver with a tiny lens mounted in a hole in the middle. The Leeuwenhoek microscope could provide resolution down to 2 micrometers (2 millionths of a meter or about 12 thousands of an inch). These early simple microscopes work by holding the lens right next to the eye and bringing the object of study close to it. The hand lens or ‘loop’ is the modern low-magnification equivalent. The tiny high power lenses could be used best with transmitted light. The compass microscope designed by Johan van Musschenbroek is of the simple type with a hinge between a handle and the plate with a lens or a ring that holds interchangeable lenses of differing magnification. On the screw barrel type of simple microscope the barrel is screwed up or down to bring the specimen into the focal plane of the lens. They were usually mounted to a handle or came with a collapsible stand. Simple microscopes were sometimes mounted to a post on a stand, an arrangement called ‘botanical pattern’ today. Aquatic microscopes with glass stages on which to place water samples and dissecting microscopes with wood or brass stages and sub-stage reflecting mirrors were produced from the mid-1700s.
The compound microscope, which is comprised of 2 or more lenses aligned along an axis in a tube, was developed in the mid-1600s. The first compound microscope we know of was constructed for Robert Hooke, who worked with Christopher Winn at Oxford and published the first book on microscopes and objects under magnification, Micrographia, in 1665. Initially, a hand held tube, compound microscopes were soon mounted to a side pillar with a base so they could be rotated at an angle and objects illuminated with a magnifying glass on a stand known as a bulls eye condensing lens. An improved design that appeared around 1725 and called the Culpeper-type after instrument maker Edmund Culpeper, was the first compound microscope to be produced in any significant quantity. John Cuff designed what is now regarded as the first truly satisfactory microscope. The Cuff-type design is characterized by having a side-pillar on which the tube is mounted and moved up and down with a focusing screw. Cuff microscopes dismantle and fit into a wood box with an inset bolt in the top so it doubles as the stand for the threaded pillar and a storage compartment for accessories. The compound microscope displaced simple microscopes for high-power magnification in science only when the a-planar objective lens was finally developed in 1830 to overcome the problem of spherical aberration.
Lenses that corrected for chromatic aberration were manufactured by John Dolland in 1758 using a two-lens doublet, one against the other. One lens was made of flint-glass (lead glass), the other crown-glass (optical glass that produces low refraction). The dual lens arrangement was quickly applied to telescopes. Harmanus van Deijl made the first commercial achromatic objectives for microscopes in 1806; however, with a magnification of 100x it still only just matched the capability of the simple microscopes of the time and spherical aberration, much more pronounced in the small thick lenses of the microscope than the thinner lenses of telescopes remained a major problem Spherical aberration was finally eliminated after Joseph Lister’s aplanatic foci designs were published in 1830, and by 1850 compound microscopes would surpass its single lens partner in popularity.
The drum microscope or Martin-type was created by Benjamin Martin in 1738 as the ‘pocket reflecting microscope’. The drum microscope is basically a single tube the user simply slides within an outer cylinder to focus and with a drum-shaped sub-stage that houses a reflecting mirror at the base. Objectives and eyepieces were interchangeable on some models. Some designs in the late 1800s differed by having the outer tube attached to side posts mounted to the drum stage below and adding a focusing rachet knob. In another variation the tube was attached to a rear post. The scope is small, portable, simple, rugged and remained popular throughout the 1800s well into the 1900s. Martin’s early model was one of the first microscopes to use an eyepiece micrometer for measuring the dimension of objects under magnification. ‘Chest microscopes’, intended for the amateur and popular from the late 1700s to the mid-1800s, are small compound microscopes that dismantle for storage in a fitted wood box. The Leitz Minor-5, introduced in 1924, is a small field microscope with a collapsible hinged frame, so the instrument can be folded-up to fit in a leather pouch. The Minor-pol is the same instrument with polarizing accessories for mineralogical and petrological work.
Around 1855 large, elegant binocular microscopes with dual eyepieces on twin body tubes that converge into a single tube with a single objective appeared on the market. Construction of binocular microscopes had been attempted as far back as the late 1600s but without success. Intended to provide stereo-viewing and reduce eyestrain, they were expensive and impractical due to delicacy and inconsistent optics Thus, they remained unpopular until greatly improved versions came out in the 1930s. From the 1870s some instruments were made of nickel silver or nickel brass and oxidized brass was used on some microscope feet and posts Black enamelled steel or brass became popular in the 1890s.
The microscope stand - the entire instrument without the magnifying lenses and other interchangeable accessories - are quite varied and have evolved over the years so they help date an instrument. By the mid to late 1800s when microscope production and use began in earnest, two major types of stands dominated the market. One is the Continental stand, with the reputation of a practical research tool, manufactured mainly in Germany and include the Zeiss jug-handle stand, introduced in 1898. The other is the English stand, which is generally larger and more elaborate, delicate and complex with a plethora of accessories. Microscopes have continued to evolved in design, components, optics and other features related to progress in metallurgy, optics, manufacturing and electrical technology, but until the 1940s, some stands had remained remarkably similar in appearance for over 60 years. Binocular instruments became the norm during the 1930s, and by the 1940s variable illumination options included both substage transmitted light and overhead reflected light from the touch of a button. In the 1960s advances in lens technology included surface coatings and flat-field optics.
The microscope has been modified in various ways for specialized applications. The inverted chemical microscope, made from 1850 into the 1900s has a microscope tube mounted at an angle below the stage where a prism transfers light from the fluid or other object of study resting on an open unobstructed stage through an objective under the stage. The petrographic microscope, which was commercialized in 1838 for mineral identification and petrographic studies, is fitted with a sub-stage light polarizer and a polarizing analyser filter in the tube above the objective so the user can control the polarization of light transmitted through a transparent thin section of mineral or rock specimens for identification and genetic associated textures. Dissecting microscopes are simple microscopes with lenses on a rotating arm mounted to a stand and specimen stage. Metallographic microscopes are designed for examination of opaque metals and large forgings while in a lathe. The photo-micrographic apparatus is a microscope that can be turned to a horizontal position along a rail (optical bench) mounted with a bellows camera at one end. Horizontal refracting microscopes have been manufactured primarily for clinical use, and some microscopes from the mid-1800s are convertible from horizontal to vertical. The panoticon is a nineteenth century dual microscope/telescope with interchangeable barrels for either application. The ‘Davon’ is a dual telescope-microscope in which the objective lens of the telescope focuses in front of a microscope objective attached to the end of the eyepiece tube, which can be unscrewed for use as a microscope. The solar microscope is designed to project the image of a transparent object on a microscope slide by using sunlight.
Portable pocket and field microscopes have been manufactured from the early 1800s. The Cary-type, for example, designed by William Cary around 1822, was advertised as a pocket microscope. It is characterized by a short barrel with a cylindrical shape at the top and conical shape at the bottom. ‘Chest microscopes’ intended for the amateur and popular from the late 1700s to the 1830s are small compound microscopes that dismantle for storage in a fitted box. Some small field microscopes from the early 1900s have collapsible hinged-frames, so the instrument folds up to fit in a leather pouch. Horizontal refracting and reflecting microscopes have been manufactured primarily for clinical and botanical use, and some microscopes from the mid-1800s are convertible from horizontal to vertical.
Barrels and cylinders of early compound microscopes were made of wood (lignum vitae) or pasteboard mantled with leather, shagreen or decorated paper. Brass quickly became standard for legs and stands, and by the late 1700s most microscope models were all brass. Some makes in the last quarter of the 1800s were all nickel brass and some nickel plate. Black enamelled steel with lacquered brass became common by the early 1900s.
Accessories for the microscope include sample slides, eyepieces, objectives, micrometer eyepieces, adjustable stage micrometers, substage condensers, substage pollarizers, bulls eye condensers, interference plates, filters, tweezers, probes, sample pins and clamps, live boxes, fish troughs, heating and temperature stages, polarizing eyepieces, drawing eyepieces, camera lucida eyepieces, paraffin microscope lamps, incandescent gas lamps and arc lamps and hardness testing points that attach to the nosepiece to mention some. Early microscope slides were typically made of wood or ivory with round recesses to hold samples and glass mounts. Glass tubes were also used as slides. Slides came mostly as glass discs or rectangles of various sizes, but by the early 1900s most were cut to the standardized size we have today. Reference slides for biology, geology and medicine were produced from the late 1800s and often come in a wooden box with stacked trays of over 50 to 100 slides. Eyepiece micrometers are eyepiece lenses inscribed with a graduated line (graticules) in micrometers. Stage micrometers are mechanical stage devises that come from the manufacturer either permanently integrated into the stage or as an accessory attachment. They are used to orient microscope slides by x and y horizontal coordinates. Precision micromanipulators with gears, minute hydraulics, magnets, pins and wedges to operate tiny scalpels, pipettes, needles, wrenches, invented in 1859, can manage maneuvers down to 5-micrometer increments. The camera lucida eyepiece projects an image of the subject under the microscope for copying on paper. The Berek compensator is a variable wave plate micrometer that slides into a slot above the objective in petrographic microscopes to determine the retardation position of interference colors for mineral identification. Vertical illuminators like the Berek illuminator screw onto the nose of petrographic microscopes for reflected light microscopy. It has an objectives clamp at the bottom. The Wright eyepiece is a polarizing accessory with a 360 degree adjustable dial and a slot near the bottom for wave plates.
Telescopes
To learn more about antique Telescopes order Opticalia-Antiques’ 300-page illustrated Reference Guide to Antique Instruments of Science, Technology and Discovery. To order now, click*
Convex lenses most likely fashioned for the purpose of magnification were found in ruins in Carthage dating back to 300 B.C. Magnifying eyeglasses had been around for farsightedness since the 1300s, and Nicholas Krebs invented spectacles for nearsightedness in Germany in 1450, but no one had thought of extending the principle of magnifying lenses to enlarge distant objects until the early 1600s, and it, allegedly, happened by chance.
Most historians give credit for this discovery to Hans Lippershey, a Dutch spectacle maker, who around 1604, discovered by accident or curiosity that two concave lenses could be separated at a specific distance to magnify and focus on distant objects. He and a colleague soon applied for a patent that apparently was never granted. Galileo Galilei, considered the first preeminent ‘modern scientist’, learned of the discovery probably in early 1609 in Italy, turned the telescope into a much more powerful and practical tool, making it a marvel of technology over night with his discoveries of distant stars, the four moons of Jupiter, the rings of Saturn, and other space phenomena. He wrote in 1610 that he had delved deep into the theory of refracted light (bending light waves with lenses) and had constructed a telescope. Galileo built many telescopes, eventually achieving a magnification of 32x. He tediously mapped the orbits of the moons of Jupiter and in a very short time discovered that longitude could be accurately determined by observing their relative positions on any clear night. Although the method was impractical at sea, it was used on land by surveyors for over 200 years. Two of the original telescopes made and used by Galileo have survived and on exhibit in the Florence, Italy museum.
The Galilean telescope is constructed around two lenses, a double-convex objective on the nose of the tube and a double-concave lens as the eyepiece. This arrangement produces an upright image. The telescope is limited, however, by a small field of view and relatively low magnification. Largely for this reason, the Galilean type configuration lasted to the twentieth century only as field binoculars and to the present day as theatre glasses. The Keplerian telescope designed by Johann Kepler in the early 1600s is configured with two double-convex lenses. This results in an inverted image but the convex eyepiece provides a larger field of view and higher magnification, and an inverted image is not a distraction for astronomical or most maritime use . The Schyrle telescope, invented by Anton Schyrle around 1625, adds two additional double-convex lenses to the Keplerian style. This four-lens arrangement returns the image to an upright position. The telescope also had a reasonable field of view and higher magnification than other telescopes of its time and became the standard terrestrial telescope through the 1700s.
The transit telescope is an astronomical refracting telescope mounted like a cannon on trunnions so it can rotate in the vertical plane. This orientation, which was first devised by Ole Romer in 1675 and used in conjunction with a pendulum clock, allowed astronomers to time the passage of planets and stars across the meridian. The transit circle is a telescope that rotates within a graduated vertical circle much like a very large transit theodolite. In this configuration the instrument acts as a mural quadrant as well as a transit.
Aberration of light, both chromatic and spherical, by the objective lens degraded images in early telescopes, causing eyestrain and frustration and on-going research to correct the problem. Chromatic aberration in lenses is caused by unequal refraction of visible light or what we perceive as color. So, the blue and red ends of the spectrum do not focus at the same point, resulting in broad spurious colors around the edge of the lens. In 1757, John Dolland, a prominent scientific instrument designer and manufacturer in London, ignoring Newton’s statement, some 70 years earlier, that it was impossible to overcome the problem of chromatic aberration in lenses, combined a convex crown-glass lens with a concave flint (lead) glass lens to, in spite of the naysayers, solve the problem.
To correct for spherical aberration, telescope manufacturers could use multiple plano-convex lenses with the convex side pointed toward the front of the tube, a technique that could not be adapted to the microscope. So, with Dolland’s patent, a new breed of superior instruments called achromatic telescopes were born. With these corrections for aberration refracting astronomical telescopes became practical, From Dolland’s patent of the achromatic lens in 1758, telescopes began being manufactured with achromatic objectives and multiple plano-convex lenses in the eyepiece (typically 4 lenses). By the early 1800s, Dolland was making 9.5-inch diameter refracting scopes, and by the late 1800s, large refracting telescopes with apertures of over 40 inches were being supplied to observatories around Europe and America. The Yerkes telescope on display at the Chicago Exhibition in 1893 was 40 inches in diameter, 50 feet long and mounted on a tower 30 feet high.
Hand held refracting telescopes are categorized by the number of retractable tubes they employ. Thus an instrument may be a single-draw, two-draw, three-draw , sever-draw and so forth. Very early telescopes were made of cardboard or wood covered with shagreen, vellum or leather scrim. From the 1750s to mid-1800s most telescopes were made of brass tubes with the front barrel made of walnut, mahogany or fruitwood. Most telescopes made from the mid-1800s well into the 1900s were made entirely of brass with leather covers common on the front barrel. In the early to mid 1800s some naval telescopes, inscribed with ‘Day or Night’ on the drawtube, were designed for night and low light conditions. A three-draw telescope with red leather cover and gilt tooling, inscribed ‘1661’, is perhaps the oldest known surviving telescope and one of the oldest known optical instruments of any kind. It’s on display at the Maritime Museum in England.
The original opera glass was designed in the early 1700s as a simple small monocular telescope based on the Galilean two-lens system. Typically, opera glasses only focus 2 to 3x. They were intended from the start to be elegant and many are ornately decorated with enamel scenes or gilded with gold. Some are clad in silver, pewter, ivory, tortoise shell or mother-of-pearl.
The first reflecting telescope, which uses mirrors to collect light instead of a lens, was invented by James Gregory in 1663. A few years later in 1669, Isaac Newton advanced the concept with a different mirror configuration, producing the first truly practical reflector, the Newtonian telescope. One of Newton’s designs was only 6 inches long but could magnify 40 times which was comparable to the magnification of a 6-foot long refractory telescope at the time but without the distracting aberrations inherent to the glass lenses in the refracting type. Large reflecting astronomical telescopes took on various mirror configuration and were in use by the mid-1700s. William Herschel was using Newtonian telescopes to penetrate space at the end of the eighteenth century, and large diameter reflecting telescope mirrors were widely applied to astronomy throughout the nineteenth and twentieth Centuries. The largest single mirror in a reflecting scope is the 6-meter diameter Russian reflector in the Caucasus Mountains, constructed in 1976.
In the Gregorian reflecting telescope light is reflected by a concave mirror at the back of the barrel then relayed by a concave secondary mirror in the middle aimed at a hole in the center of the back mirror where an eyepiece lens enlarges the image for the user. Because of its relative short and compact size, an upright image, lack of chromatic aberration and large diameter objective mirror that could gather more light and penetrate deeper into space, the reflecting telescope was more popular with scientists than the refracting type well into the 1700s.
Large reflecting astronomical telescopes were in use by the mid-1700s, and James Short’s 36-inch Gregorian telescope was used to track the transit of Venus in 1769. Telescopes became bigger and bigger until limitations on weight and mirror polishing technologies lead to development of multiple mirror objectives for reflecting telescopes during the 1970s. The 30ft. (10m) diameter Keck telescope erected in Hawaii in1992 is a mosaic of 36 one-meter mirrors. The optics and movement apparatus of modern telescopes are linked to computer programs, video screens and digital recording electronics.
Binoculars & Opera Glasses
To learn more about antique Binoculars and Opera Glasses order Opticalia-Antiques’ 500-page illustrated Reference Guide to Antique Instruments of Science, Technology and Discovery. For ordering info click*
Soon after the invention of the telescope around 1607, opticians began to experiment with parallel arrangements of two telescopes or ‘binoculars’, which means ‘two-eyed’. Binoculars were developed by the mid-1600s and the oldest one known in existence today was made by Cherubin d’ Orleans around 1670. It is designed as a gift, constructed of two telescopes mounted inside an elegantly gilded, rectangular box.
Because of the short tubes, early binoculars were constructed with the Galilean lens arrangement and are called Galilean-type binoculars. The double-convex objective and double-concave eyepiece, results in powers little better than 3 to 4x., providing an inferior contender to the multi-lens, higher power terrestrial telescopes. It wasn’t until the late 1800s when creative designs began to appear and people began to appreciate the compactness and convenience of binoculars that they were produced in quantity as ‘field glasses’.
For example, in the 1880s ‘telescoping’ binoculars with 4 lenses in the eyepiece tube were offered. These long binoculars are basically two Schyrle-type telescopes mounted in parallel. Some are large but lightweight, with aluminium bodies, and can magnify up to 16x. They were popular in the military during the World Wars. By the late 1800s refinements on some binoculars included sling loops for straps, sunshade cylinders and hinged bridges or ‘bosses’ to adjust for differences in eye separation from user to user. Aluminium construction rather than heavier brass was becoming more common.
Although the technology had been available for some time, it wasn’t until nearly the turn of the century that a truly successful prismatic binocular was developed. In 1894, Professor Ernst Abbe teamed up with the Zeiss Company to produce the Feldstecher (German for field glass), using Porro prisms. The largest model magnified to 8x. It has individual screw focusing eyepieces and a hinged bridge connecting the two tubes, thus is adjustable for eye separation.
Prismatic optics revolutionized the binocular by using two prisms back to back or other arrangements of prisms to rebound light and effectively extend the distance between objective and eyepiece thus compacting the tube while at the same time increasing the ratio of focal lengths between the two lenses, resulting in higher magnification. The prisms also widen the distance between objective lenses thus enhancing the stereographic perspective or perception of depth.
By 1910 binoculars were produced in large quantity for both military and civilian use in several countries and invariable come with leather sling cases. Binoculars became more diverse and large, heavy, rugged brass binoculars made for navy boat decks contrast with small, dainty feminine opera glasses. Illumination and brightness were greatly improved in the 1930s when a thin coat of magnesium fluoride was applied to glass surfaces to reduce distracting reflections.
The original opera glass was designed in the early 1700s as a simple small monocular telescope based on the Galilean two-lens system. The first binocular opera glass was introduced in 1823 and consisted of two small telescopes joined by a stationary bridge with each side focused independently. Typically, opera glasses only focus 2 to 3x. They were intended from the start to be elegant works of art and many are ornately decorated with enamel scenes or gilded with gold. Some are clad in silver, pewter, ivory, tortoise shell or mother-of-pearl and some are attached to a telescoping hand hold called a ‘Lorgnette handle’. Most opera glasses come in plush silk-lined leather cases or silk draw-string bags.
Meteorology & Barometers
To learn more about antique Barometers and Instruments of Meteorology order Opticalia-Antiques’ 500-page illustrated Reference Guide to Antique Instruments of Science, Technology and Discovery.For ordering info click*
The word ‘barometer’ comes from the Greek root, ‘baros’ which means weight. But the barometer actually measures pressure rather than weight – atmospheric pressure. The earliest barometer like instrument was called a weatherglass or thunder glass, because it could predict rain. The weatherglass consists of a glass pitcher, sealed at the top, with a glass spout attached low on one side. When filled half way with water, the level of the water in the spout rises or falls in response to ambient air pressure, or barometric pressure. If pressure is low and the water rises, rain could be on the way.
Mercury was first used in a barometric experiment in 1643 by Vincenzio Viviani in collaboration with a student of Galileo’s named Evangelista Torrecelli. Viviani filled a thin glass tube with mercury, placed a finger over one end and submerged the other end into a pan of mercury. When he removed his finger, the mercury in the tube settled to a lower height in relation to atmospheric pressure.
The earliest mercury barometers are called, collectively, cistern or stick barometers. There are two basic designs. The earliest and simplest is called an open-cistern barometer, which is simply a long glass tube with its bottom submerged in a cup filled with mercury. Bulb-cistern barometers differ in that the tube has a gooseneck at the bottom that bends up into a mercury filled bulb with an opening in its top. The registering plates are commonly inscribed ‘Very Dry, Dry, Settled Fair, Fair, Changeable, Rain, Much Rain, Storms’. Siphon-tube barometers have a ‘U’ shaped tube at the bottom with the short end simply open to the atmosphere.
To improve precision, since extremes in atmospheric pressure only move a mercury column about 3 inches, Samuel Morland invented the angle tube barometer, also called the yardarm, diagonal, or sign post type, in 1670. The tube on this instrument extends 36 inches at a slight angle to the horizontal but only rises 3 inches vertically while moving 36 inches horizontally, a configuration that allows measuring gradations in pressure over a 36-inch scale, which is a 12 to 1 improvement over the 3-inch scale of the stick type. The instrument did not work in practice as well as in theory and was not popular.
The first specially designed marine barometer was constructed by Robert Hooke in 1667. It consists of a pair of parallel thermometers about a foot long. One is a mercury-air thermometer, the other a spirit thermometer. As the mercury level changes it is calibrated to the temperature reading on the spirit thermometer. Hooke devised another instrument called a restricted tube barometer that was intended for sea. It is simply a long barometer with a constricted segment of tube just above the cistern.
The other common marine barometer is called the sympiesometer, a double-tube barometer-thermometer patented by Alexander Adie in 1818. It consists of two short tubes about 24 inches long. One tube has a closed bulb at the top filled with hydrogen and a restricted open bulb cistern at the bottom filled with colored almond oil. The other tube is a standard mercury thermometer. Hydrogen volume and thus the level of oil in the pressure tube varies with changes in atmospheric pressure and temperature. The reading is calibrated to temperature using the thermometer. Small pocket versions of the sympiesometer, are only 6 inches long.
The Kew marine barometer was developed following an international conference on meteorology held in Brussels in 1853. The Kew is a cistern-type stick barometer encased in a brass cylinder attached to gimballed brackets for mounting to cabin walls or posts.
The wheel barometer has a long history but became popular in the mid-1700s. The instrument gets its name from its internal workings: the glass tube is ‘U’ shaped at the bottom with a ‘float’ resting on the mercury column in the short limb of the ‘U’. The float is connected to a silk string that passes over a pulley wheel with a small weight tied to the other end. The pulley is connected to an indicator needle. The wheel barometer became astonishingly popular in the domestic market and was often artistically designed with ornately carved frames, ivory and mother-of-pearl inlay. Indeed, the barometer is classified by the shape of its carved top. For example a scroll wheel barometer has a scroll design on top and a pediment wheel barometer a flared flat top.
The importance of the barometer for measuring altitude lead to various attempts during the 1600s to construct a small, durable, portable and precise instrument. The first practical mercury barometer produced for mountaineering and elevation surveying was designed in 1770 by Jean-Andre Deluc. He focused on improved precision by using boiled mercury, devoid of air; innovative levelling methods; a new meniscus interpolation method; and his temperature compensation invention called a hypsometer. His instruments were accurate to 0.01 inches.
Then the ‘aneroid’ emerged and everything changed. In 1843 the barometer was revolutionized by a radical new invention that would eventually make the mercury barometer obsolete. Lucien Vidie created a metallic pressure indicator he called an ‘aneroid’ which means ‘dry’ or ‘without liquid’. For the sensitive pressure detector he used a sealed brass box with a corrugated diaphragm supported by helical springs. A popular pocket-sized aneroid barometer only 2.5 inches in diameter was developed by Negretti & Zambra in 1860.
A type of aneroid barometer that graphs changes in barometric pressure on paper and called a barograph was produced from around 1865. The expansion and contraction of a metal cylinder attached to the barograph moves an arm attached to an ink pen in contact with graph paper attached to a revolving drum driven by a mechanical clock.
The thermometer, known to have been used by alchemists by 1610, may have been invented by Galileo, but is known to have been improved by him. The earliest type, the water thermometer or thermoscope, was a helix shaped glass tube with an air filled bulb at the bottom to push a water column up the tube when heated. More effective liquid thermometers were made around 1640 with wine. Marking freezing and boiling points on thermometers became practice in the late 1600s with mercury thermometer, beginning with the Fahrenheit scale then Celsius scale in 1740. The ‘metallic’ thermometer, which appeared about 1910, is a circular wall mount in a wooden frame with a dial and indicator needle that resembles a clock and popular in the domestic market. Most early simple mercury thermometers were mounted to ivory, brass, copper, wood, porcelain or agate, marked with graduated scales; metal was typically preferred for outdoor use. Thermometers that leave an indicator where temperature reaches a low were developed to record minimum temperatures and are usually mounted alongside regular thermometers, the pair called maximum-minimum thermometers. A solar radiation thermometer measures maximum temperature of solar rays in open air and dates to the late 1800s. It consists of an outer tube about a foot long with a large 2-inch diameter glass bulb vacuum chamber at one end with a mercury thermometer suspended inside the outer tube. An instrument developed in 1820 consisted of a ‘U’ shaped glass tube with bulbs on each end and filled with ether with a thermometer attached alongside. The temperature at which the ether evaporates from one end of the tube and condenses on the other determines the ‘dew point’. Another method of measuring humidity is by comparing wet and dry bulb thermometers. One thermometer is connected to a tube with water and kept wet, so the difference in temperature between the two indicates humidity. The thermograph is a small cabinet-housed, pen-operated, temperature recording devise that graphs temperature changes on graph paper.
Others include the thermograph, a pen-operated temperature recording devise that graphs temperature changes; the hygrometer for registering humidity; anemometers and anemographs which measure and record wind velocity, respectively; and instruments that measure rain fall and water flow like rain gauges, current meters, flowmeters and wave predicting devices. Cloud phenomena and formation are studied with instruments like the nephelescope, invented in 1835, the nephoscope and the cloud chamber, invented in 1895.
The meteorograph is a complex multi-task instrument that automatically records several meteorological parameters at the same time onto a single graph. George Dolland’s meteorograph on show at London’s Great Exhibition of 1851 could measure and record eight parameters at once. Radiosondes, small meteorographs that mount to weather balloons first used in 1892 and in 1896 carried a thermometer, barometer and hygrometer which is still the standard three-sensor package.
Calculating Devices
To learn more about antique Calculating Devises order Opticalia-Antiques’ 500-page illustrated Reference Guide to Antique Instruments of Science, Technology and Discovery. For ordering info click*
Calculating devises are the tools used to facilitate and accelerate mathematical calculations. They have progressed from simple hand-manipulated beads; to sliding rods; to discs and rules; to mechanical machines; to electro-mechanical devises; and finally to electronic instruments and computers.
Counting rods, used in Asia and uncovered at archaeological sites, date to the second century BCE They are small dowels about 6 inches long made of bamboo and other woods. A standard set of counting rods contains 271 rods. Although the earliest written account of an abacus as we generally think of them, with beads that slide along a bamboo rod or later on metal rods, is from the 1500s, it is believed by some historians that the Romans and Chinese were using them by the third century CE Remarkably, the abacus is still in use in China and other parts of the world today.
The first devise generally recognized as a mechanical calculator is the sector. The elementary design of two flat 6-inch rules, hinged together, evolved through the second half of the 1500s. Then in 1598, Galileo enhanced and improved the basic instrument into what was to become known as the universal sector for general calculating. Sectors are made of ivory, boxwood, brass or silver. Interestingly, the sector was still being manufactured and used by scientists and draftsmen right through the 1800s.
In the early 1600s, John Napier perfected a clever way to multiply and divide that became known as the principle of logarithms. He fashioned a set of square-sided rules that become known as Napier’s rods or Napier’s bones since they were originally made out of ivory. Close on the heals of Napier’s bones was William Oughtred’s invention around 1625 of the proper slide rule which was called ‘circles of proportion’. It consisted of a thin, flat circular brass disc with a smaller diameter disc in the center. It is amusing to know that Oughtred resisted publishing his results for over three years because he was concerned his invention would make math too easy, and students would avoid learning to calculate math manually. Some things never change.
The oldest known surviving example of a linear slide rule, which was made by inventor Robert Bissaker, dates to 1654. The standardized rectilinear design with scales familiar to us today is based on the Mannheim rule invented about 1853. Slide rules were originally made of brass, ivory or boxwood and later thermoplastics. The grid slide rule was invented by Joseph Everett in 1866. It is flat, rectilinear, and segmented into short parallel rules with an effective length of 40 feet.
The Fuller calculator was introduced by George Fuller in 1878. It has an effective 42-foot long scale accurate to within 1 to 10,000 spiralled around a hand-held 3 inch diameter, 12 inch long wood tube. In 1881, Edwin Thatcher designed a tabletop slide rule that bears his name. It too is cylindrical, 4in. in diameter and 18in. long. One of the most popular pocket size, tubular styles, especially in Europe was the Otis King calculator which began production in 1922. The slide rule remained the basic tool of engineers and scientists until introduction of the hand held electronic calculator in 1971.
About the time the slide rule was becoming the pocket calculator of the scientist, a simple calculating machine was described by Wilhelm Schickard, and in the late 1600s, Gottfried Leibniz introduced a cylindrical geared computing devise that could add, subtract, multiply and extract roots and looks remarkably similar to the mechanical calculating devises of the early to mid-1900s. These devises remained more objects of curiosity than practical tools until 1820 when Charles Thomas invented an arithometer with levers and a geared drum. In 1895, O. Steiger patented a machine that could multiply with one pull of the handle. An arithmetical machine called the Curta consists of a small 2.5 inch diameter, 3.5 inch tall cylinder with a handle on top and vertical adjustable scales along the sides of the cylinder. It is named after its inventor and was perhaps the highest quality small calculator invented.
The unveiling of the transistor in 1948 and invention of the microchip in 1959 led eventually to mass production of inexpensive hand held electronic calculators, beginning in 1971 with Texas Instrument’s pocketronic, rendering the calculating machine and slide rule obsolete virtually overnight. As soon as three years later Hewlett Packard started marketing a programmable pocket calculator and a year later the first personal computer in kit form was introduced. The Apple II hit the stores in 1977 and by the early 1980s desktop computers were becoming commonplace.
Drawing Instruments
To learn more about antique Drawing Instruments order Opticalia-Antiques’ 500-page illustrated Reference Guide to Antique Instruments of Science, Technology and Discovery. For ordering info click*
Drawing instruments are among the oldest tools of humankind. They are inferred to have existed from ancient archaeological drawing and have been recovered from archaeological digs at Greek and Roman sites. For example, a scale rule and scribe are depicted on a Babylon architectural plan from 2150 BCE A set of bronze instruments dating to about 80 CE that includes callipers, dividers and square rules were found in excavations at Pompeii.
Early styli, perhaps the most fundamental of drawing instruments, were the precursor of the modern pen and pencil. They were scoring tools used to incise lines or trace along the edge of a rule on parchment, vellum or waxed tablets. Early ruling pens have two metal prongs with pre-set gaps to hold the ink. Then in the 1600s, they were fitted with screws for adjusting line width.
By 1660 charcoal dowels were being glued between two halves of wood and marketed as ‘dry pencil’ to distinguish it from ‘pencil’ which at that time was a fine haired paint brush. The only major change to occur in the pencil was in 1940 when several firms began to market the now familiar automatic technical pencil called ‘drop action’ in which a spring clamp releases fine lead by pressing a button. The first practical continuous technical pen was the Graphos invented by Gunther Wagner in 1932. The Rapidograph was manufactured by Wilhelm Riepe from 1952. It had interchangeable tubular nibs and a capsule reservoir held in the handle.
Rules are basic straight edges for drawing straight lines of if a French curve for drawing curved lines. Square sets are triangular rules that allow a predetermined angle to be drawn. Scales are rules with a graduated scale along one or both edges so a predetermined length can be drawn or a line distance measured. Parallel rules are composed of two separate rules with pivoting hinges for drawing parallel lines, and rolling rules have cylindrical rollers inserted through them so the rule can be rolled to maintain parallel lines. Many rules have a graduated scale along the edge so a line of predetermined length can be drawn or a line distance measured.
Dividers and compasses are two pencil-like pointers connected by a pivot joint at one end. Usually made of steel, brass, nickel or silver, they may be ornately engraved. They range in length from about 2 to 12 inches. Dividers are used to repeat distances along a scale or measure at set increments on a drawing or map. Compasses are identical to dividers in basic design but since at least the 1300s one point could be used for scoring or for drawing an arc or circle. Compasses come in different designs primarily to accommodate different size circles. They include wing-compasses , screw-compasses, bow compasses, spring bow compasses, beam-compasses, which are two separate attachments devised by Leonardo da Vinci around 1492 to draw unusually large circles, pillar compasses, turn-about compass, and the pump-compass, which is a small pencil-like tube for drawing pinhead sized circles. As a drafting tool the sector provides results graphically and must be accompanied by a divider.
The proportional compass, is the earliest and simplest version of reducing and enlarging instruments. They have two pointed arms like dividers, and operate line by line. The more complex and much larger pantograph was invented about 1603 by Christoph Scheiner. It is a large drawing apparatus typically about a meter long with four pivoting arms. The arms are hinged and articulated such that one pen draws a larger version of the other. The ediograph is an 1821 improvement over the pantograph that incorporates three arms with cables and pulleys.
Devices that project images can be used for copying and enlarging. The earliest known instrument like this is the camera obscura or pin-hole camera, crude forms of which have been around since the fifth century. The camera obscura, predecessor to the photographic camera, is a box with a hole in one side, through which an inverted image of an outside scene is naturally projected onto the opposite side, or in the case of a dark room or tent onto the opposite wall. They were refined during the 1600s to include a converging lens. The camera lucida was patented in 1806 by William Wollaston for drawing copies or reductions from an original. A prism reflects the image of a distant scene or subject onto a sheet of paper below the prism over which the user can place a transparency and copy the image. The camera lucida was popular with artists throughout the nineteenth century and lived on throughout the twentieth century in some drawing, drafting and photogrammetric labs.
The planimeter is a mechanical drafting and engineering tool that measures the area bounded by a closed curve. It consists of a rotating disc linked to a tracer that rolls against a cone to measure the area swept by the tracer. The protractor is a flat circular arc graduated in 360-degree marks or more commonly a semi-circular arc graduated in 180° that is used to measure and draw angles. Square sets are usually flat straight edged triangles with one right angle in combination with either two 45° angles or 30° and 60° angles.
From the 1500s, sets of drawing instruments were provided in portable boxes. The larger and more comprehensive sets in plush lined hardwood inlay boxes with brass medallions are more valuable and collectable. Metal instruments in old drawing sets are made mostly of brass and steel, occasionally silver. After 1850 some were made of German silver or nickel silver (alloy of copper, zinc and nickel) and by 1900 mostly electrum (nickel and copper). Pocket sets from the 1700s and early 1800s are small round to flat canisters often elegantly made in silver, shagreen, shark skin or tortoise shell.
Engineering & Technology
To learn more about antique instruments of Engineering and Technology order Opticalia-Antiques’ 500-page illustrated Reference Guide to Antique Instruments of Science, Technology and Discovery. For ordering info click*
The distinction between instruments of science and those of engineering and technology is nebulous. The two have progressed hand-in-hand in mutual dependence, which has lead some authorities on antiques to lump them together. For our purposes we include along with the standard repertoire of instruments of engineering and technology those of physics, geophysics and the so-called philosophical instruments. Fundamentally, all scientific instruments are instruments of technology inasmuch as they represent contemporary technological expertise. Science depends on the ability of engineering to create devises that apply to study and new discoveries as well as to provide the instruments scientists need to conduct further investigation, study and experimentation.
We can broadly classify engineering and technological instruments as those used for communication, transportation, photography, energy conversion, comfort, convenience, entertainment, production, construction, mining, manufacture, monitoring, engineering and geophysical models and most testing and electrical devises. Technological items used by scientists may have special or historical significance and be included with collections of scientific instruments. Technological progress has been in the fast lane for the past 100 years and even more rapidly telescoped over the past few decades. For this reason, items of technology can become collectable in a relatively short period of time. Since there are thousands of engineering and technology instruments, we can only mention a few of them here.
The magic lantern, the precursor to overhead or slide projectors, was invented in 1643 and originally used candlelight to project an enlarged image on a wall or other flat surface. Solar microscopes were also invented in the seventeenth century along similar principles. They are small brass tubes mounted to a brass plate (rarely silver) and use sunlight to project a large image of a microscope slide.
Fixed photography was invented about 1827 and hardwood cased bellows cameras with brass fittings were made into the early 1900s, becoming common after dry plate film was developed around 1870. The larger the camera, the larger the photograph, a line of logic that lead to creation of the world’s largest camera in 1858, ‘The Mammoth’. It was over 15 feet long, used 500 lb glass plates and weighed 1400 lbs loaded. Continuous roll film was patented in 1885, leading to the first roll film box type camera from Kodak. Kodak’s famous Brownie line of cameras sold in the millions from 1900, and in 1921 the modern 35mm camera with interchangeable lenses was introduced by Leica. The oldest existing photographs of people are from 1840 when they had to sit still for about a 20-minute exposure time and when subjects were held often held rigid with head and arm braces.
Motion picture cameras began recording crude films in the 1890s. Stereoscopes (both table top and hand-held) became the rage of home entertainment after Sir David Brewster’s improved viewer was displayed at the Great Exhibition of 1851. They operated off the principle of parallax where two images or photographs of the same subject but at slightly different angles are viewed side by side so they are seen in 3-D.
About the time Christiaan Huygens was developing his pendulum clock, Robert Hooke was experimenting with spring drives, and by 1700 the clock was a portable devise that could keep time to within a minute. Atomic clocks, first developed in 1949, use electromagnetic oscillations generated by energy state transitions within an atom.
Literally hundreds of items have been invented in the field of electricity, beginning with Francis Hauksbee’s electrostatic machine in 1706. In 1746, the Leyden jar was invented to store static electricity generated by the electrostatic machine. A year later the first electrometer was devised to detect electric potential difference between two repelling conductors. Plate condensers and voltaic piles were invented in 1778 and 1799, respectively, to build and store electric charge. The torsion balance, which detects both electrical and magnetic forces, appeared in 1784.
A galvanometer, the precursor to the familiar voltmeter and ammeter, was designed by James Cumming in 1821. It had coils and a magnetic needle that was deflected proportional to electromagnetic currents in the galvanometer coil. Cumming created the first thermopile two years later to demonstrate the thermoelectric effect. In 1834, Jean Peltier discovered that passing an electric current through a thermopile produces heating or cooling at one end of the thermocouple and used the devise to freeze water.
Invention of the magneto-electric machine and induction coil is attributed to Michael Faraday and Joseph Henry in 1830. The magneto-electric machine or dynamo is the proto-electric generator. When a coil of wire is rotated within a magnetic field created by opposing magnets an electric current is induced in the coil. The induction coil was first used for medical shock therapy, and was popular in medicine well into the twentieth century. The Wheatstone bridge, invented in 1843, is used to make precise measurements of resistance.
There were five important commercial instruments for measuring various electrical parameters developed around 1882 in response to interest in electric lighting: the voltmeter, ammeter, ohmmeter, wattmeter, and electric supply meter. Many of these small instruments are mounted in attractive hardwood cases with gauges and brass fittings. Geissler tubes, invented in 1850, evolved into colourful twisted glass conversation pieces, then into the microchip in 1959. Electric powered lighting remained impractical throughout most of the nineteenth century, but experiments with lighting lead to the arc-lamp of 1808, which used two carbon rods and then to the carbon filament lamp invented by Thomas Edison in 1879. Prior to electric lighting in the 1880s and a source to direct intense light, scientists used the heliostat, dating back to Willem Gravesande’s invention of 1742. Heliostats use mirrors attached to a rotating arm powered by a clock mechanism that follows the sun in order to keep the projection of light stationary for a variety of purposes.
Around 1855, Hermann von Helmholtz invented the Helmholtz resonator. It is a hollow sphere with necks at opposite poles. One neck is made narrow in order to enter the ear. They are usually made of glass or brass and come in sets of graduated sizes. They became a physiological basis for understanding tones and stimulated research in acoustics. Sonometers are mechanical devices that probably date as far back as the sixth century BCE. It is simply a long box enclosing one or more strings that are free to vibrate in order to resonate and magnify the sound. These mechanical devises were replaced by sound meters – electroacoustic instruments that measure sound pressure levels in decibels.
Communication by written word reached an historic milestone in 1454 with the invention by Johann Gutenburg of the Gutenburg moveable type press. Modern communication technology dates to the invention of the telegraph in 1831, Guglielmo Marconi’s wireless telegraph in 1894, Alexander Graham Bell’s invention of the telephone in 1876, satellite phones and cell phones from the late 1980s and the first television sets in 1936.
The field of transportation could take up a museum of its own dating back to centuries old horse drawn carts and chariots and dugout canoes to the first chain driven bicycle invented in 1859. Mechanized transportation began with steam engines, first invented in 1698 and installed on a paddleboat in 1781, then on a steamboat by Robert Fulton in 1803. Electricity has been used to propel vehicles, perhaps most dramatically from 1881 when the first electric streetcar was introduced in Berlin. The first internal combustion engine, a highly inefficient design, was invented in 1859. Then improved high-speed versions were placed on a boat by Gottlieb Daimler in 1883 then on a bicycle. In 1887 Karl Benz installed an internal-combustion engine on a 3-wheel vehicle, creating one of the first automobiles.
Experiments with airplanes began in full earnest around 1890 when Clement Adler’s Eole lifted off the ground under its own power. Samuel Langley flew his steam-powered airplane over a kilometre before crashing in 1896, and G. Whitehead performed the first flight on a motor-driven airplane in 1901. Then the first sustainable and successful engine driven flight from take off to landing in a reusable airplane was performed by the Wright brothers in 1903.
We place instruments related to manufacturing, mining, farming, construction, fishing and fabrication in the category of Engineering and Technology. Gauges have been in use since men used poles with depth gauge marks to determine the amount of wine in a barrel. Meters, indicators, process controllers, tachometers and governors have been manufactured for hundreds of purposes described in more detail in the Reference Guide.
Micrometers measure small divisions of length, width, depth and angles and have had phenomenally widespread application in both science and engineering. Cathetometers are a precision instrument developed around 1810 to measure the difference in level or height between two points such as the surface dilation of a mercury column. The spherometer was designed to measure thickness of thin plates and to measure curved surfaces. Calipers in a myriad of designs for a multitude of purposes, some with lever magnification gauges, date back to more basic designs in the 1700s.
Miniature models of steam and internal combustion engines, milling machines, locomotives, hydraulic and pneumatic machines, dozers, tractors, stamp-mills, ore jiggers and numerous other items have been made from the time it’s original full scale counterpart was first manufactured. Collector’s enthusiasm for models was sparked when the U.S. Patent Office sold hundreds of models it had in its possession in the 1920s. Models have also been provided by the manufacturers of the full-scale item for purposes of display and for salesmen to show potential buyers, and they have been made by individual hobbyists, professional model makers and toy manufacturers.
Devises made to observe physical and electrical phenomena dating to the seventeenth century, are often described under the heading of ‘philosophical instruments’. Many of these items became legitimate instruments in the field of physics. They include such devices as frames with pulleys and weights, centrifugal force devises, unusually balanced gravity models, magneto-electric demonstration apparatus, air pumps, the Archimedes screw (a helix which when rotated moves a ball up hill apparently defying the force of gravity), the invisible force of repelling magnets, color combining wheels, wave vibration plates, and many other instruments.
Everyday technology includes such things as continuous sewing machines which Isaac Singer patented in 1851, refrigerators from the late 1800s, geared tools for the kitchen like grinders and apple corers, washing machines, electrical fans, lamps, signalling devises, heat detectors (thermostats) dating to 1873, clothes irons, music boxes, locks, latches, cork screws, can openers, games and toys, certain models, most clocks and watches and the bulk of cameras. Many items of collectable everyday technology began as mechanically driven devices, evolving to electro-mechanical versions. For example, the mechanical typewriter, invented by William Burt in 1829, became electrically powered in the early 1900s, and phonographs and gramophones dating to the late 1890s evolved to electric record players in the 1920s.
Medicine
To learn more about antique Medical Instruments order Opticalia-Antiques’ 500-page illustrated Reference Guide to Antique Instruments of Science, Technology and Discovery. For ordering info click*
Medical instruments include devises used by doctors, dentists, ophthalmologists, optometrists and veterinarians. Prior to the 1800s, there was little distinction between these medical disciplines or between them and other disciplines for that matter. In fact, barbers and chemists served as doctors and continued to drain blood from sick patients following the ancient texts of Galen. Instruments used for medical purposes date back to Egyptian, Greek and Roman times, and the scalpels and saws found in ruins of antiquity are remarkably similar to their modern counterparts.
Cutting instruments, including scalpels, saws and knives, needles, forceps, hand drills, probes and trepanning tools (made to cut or drill holes in the scull) are among the oldest medical instruments, dating to the 1600s and earlier. Catheters, usually made of silver, date to the time of the Romans. Cased, fitted, surgical, midwifery, lithotomy and post mortem kits dating from the late 1700s well into the 1900s are highly collectable.
The sphygmograph was invented in 1860 by Etienne-Jules Marey. It had a small frame that strapped to the forearm with a pulse sensitive lever that rotated a writing arm in order to graph the pulse rate. The sphygmograph lead to development of the sphygmomanometer by Samuel von Basch in 1881. In 1886, Scipione Riva-Rocci developed the now familiar inflatable rubber arm band that connects to a mercury manometer. The hemoglobinometer measures the amount of red pigment in blood. The crude method of reference to graded red and pink colored dots devised by Theodore Tallquist in 1900, is still used in some parts of the world. The haemacytometer, is a pair of small thermometer-like pipettes for examining white and red corpuscles.
The widely recognized binaural stethoscope with two ear tubes, used by doctors to amplify sounds in the chest cavity related to cardio and respiratory conditions, was patented in 1855. The earlier version, the monaural stethescope is simply a wooden tube, occasionally silver or ivory, invented in 1816, that has a flared end like a bugle the doctor holds against the chest or back while listening at the other end. Its ability to amplify sound is still debated, but it was made well into the twentieth century. Craniometers and cephalometers originated in the 1820s and 1838, respectively, to relate the shape of the human skull to mental attributes (phrenology) and other characteristics. Lab mice are sometimes mentioned as scientific instruments because of their importance in biomedical research. I haven’t seen one but there must be a taxidermy specimen of a famous white mouse somewhere that was used in some earth shaking medical research, but I bet it will not have come from the labs of a cosmetic company.
Numerous devices have been created over the years to test the senses. Invented in 1711 for musical purposes, the tuning fork became important in physics and hearing applications a century later. They were activated by electronic vacuum tubes during the 1920s and superseded by electronic devices by the end of the millennium.
The audiometer was originally an electric induction coil device, then speech audiometers appeared in 1904 based on Thomas Edison’s phonograph. The Galton whistle was invented by Francis Galton in 1876 to produce frequencies high enough to test the limit of pitch audible to humans and animals. An Olfactory tester from the early 1800s tests smell sensation, discrimination and perception by using two glass nostril tubes inserted through a board with the hidden test sample on the back. The Tachistoscope is a device that tests a person’s visual attention and response time to a variety of stimuli. Early tachistoscopes from the 1890s used falling screens and other mechanical devises. Modern ones are electronic and digital, using varied illumination, fields of view and timers.
Electrical shock treatment began in the 1700s, and in 1782 a medical electrical machine or induction coil was patented by Edward Nairne. Many machines dating to the 1800s use a small generator and a large bar magnet connected to wheels and a crank that’s wired to two brass handles to shock the patient. Sensitive string galvanometers consisting simply of a single filament hung between the poles of a magnet, were used in 1897 by medical doctors as electrocardiographs to record electric currents generated by heartbeat through electrodes applied to the chest. A similar electroencephalograph was used to measure electrical activity in the brain using electrodes attached to the scalp in 1902. These devises derive from the kymograph, an instrument invented by Wilhem Wundt in the 1840s.
Galvanometers were also used as the first electromyographs to detect electrical currents related to muscle action in 1844 and electroretinographs to study electric potential in the retina related to reaction to light intensity in 1849. These recording instruments evolved into bulky, cumbersome and not very practical instruments through the 1800s to be replaced by highly efficient computerized systems by the late twentieth century. The polygraph, well known today as the lie detector, is a physiological instrument designed originally in the 1860s to study interrelationships between the respiratory system, pulse rate and muscle nerve reaction simultaneously and graph the results. It combines a cardiograph, sphygmograph, air tubes and tambour.
Optometry originated with magnifying eyeglasses to correct for farsightedness in the 1200s CE but it was largely a trial and error practice. Then in 1450 Nicholas Krebs invented distance spectacles for nearsightedness. Eye surgery tools are more delicate than general surgery instruments and many, like the cyst and ulcer scoop, corneal splitting wedge, and some scissors, needles, probes and scalpels are specialized. Sets of eye surgical instruments were arranged in fitted wooden boxes. Eye testing kits or trial cases can include over 100 bi-convex and bi-concave lenses and accessories arranged in a fitted box.
The ophthalmoscope, invented in 1850 by Hermann von Helmholtz, is a clever diagnostic instrument that reflects indirect light into the eye so a physician can view the retina. Around 1915 ophthalmoscopes were fitted with dry cell batteries. The ophthalmotonometer, which measures the inter-ocular pressure in the eye was invented in 1862, but only came into general use after 1905. The retinoscope, introduced in 1873, is simply a beam of light passed over the patient’s pupil from which the examiner estimates refraction error from the retinal reflection. The variator, an advanced type of retinoscope invented in 1932 uses adjustable telescopes that act as correcting lenses to measure refraction error.
Dentistry only emerged as a sub-discipline of medical science around 1830 and ‘professionals’ practicing at that time were poorly trained if trained at all. Still, tooth filling dates to the early third millennium BCE, and a form of cosmetic false teeth were fashioned by the Etruscans around 970 BCE Specialized scalpels, probes, forceps, lancets and other delicate tools have been designed specifically for dentistry and can be found as sets. During the middle ages a specialized tool for tooth extraction was called the ‘pelican’ because of the shape of its pinchers. The tooth key, invented in 1742, consists of a key operated claw attached to a wood or ivory handle. Dental burs linked to long thin hand-operated spring gears for grinding teeth and different types of pluggers for packing gold into fillings were patented during the mid-1800s. In 1790 George Washington’s dentist, John Greenwood devised the first powered dental drill, using a spinning wheel as the power source. A motorized dental drill was developed around 1860 and the high speed ‘painless’ drill much like our modern ones was invented in 1957. Pain is a relative thing.
Other collectable medical devices include prostheses, plaster phrenology models showing where the various mental facilities were believed to reside, wax and plaster models of body parts, glass eyes (invented in 1580), wheel chairs, medicine chests and boxes with bottles, medicine cabinets, physicians travel bags, early x-ray radiographs dating to 1900, hypodermic and serum syringes, dynamometers, hearing aids such as electrical aids dating from Millar Hutchinson’s hearing aid invented in 1902, bacteria culture sets or ‘Museum’ cultures for microscopic viewing, brass or pewter enema syringes dating to the 1700s and dozens of additional items.
The veterinary field is a branch of medicine that uses many of the same instruments as human medical science, modified and specialized for animal physiology. Many devices of veterinary practice, however, are unique to the animal species and its medicine, breeding and husbandry.
Navigation & Nautical
To learn more about antique Navigational Instruments order Opticalia-Antiques’ 500-page illustrated Reference Guide to Antique Instruments of Science, Technology and Discovery. For ordering info click*
Navigational instruments are mainly those used at sea, but could include any devise used to locate oneself on land or water or in the air and determine direction for the purpose of travel. Many historians believe it was the practical need for improved navigational abilities in the 1400s that sparked the prolific development of scientific instruments in the first place. The compass and telescope are fundamental tools for navigation, and they are described in sections of their own. In this section we will look at some of the other instruments that are commonly categorized as navigational.
The astrolabe, which means ‘star-taking’, has been around since the third century CE. It is a metal disc, most commonly brass, inscribed with the position of prominent stars, sun and moon at various times of the year and originally used by astronomers. They were inscribed with 360 degree marks around the edge or limb and mounted with a sighting bar or alidade that pivots in the middle of the disc in order to measure angular distances of planets, stars, sun and moon. The astronomical astrolabe was already an ancient devise when it was modified for ocean navigation in the 1300s. The specialized design was open-frame to make it lighter and easier to handle in wind. The astrolabe is essentially the earliest analogue computer since it could actually determine time if the day of the month were known. No wonder it is considered the archetypal scientific instrument along with the quadrant. Improvements in the astrolabe and the quadrant, a quarter circle arc marked from 0-90° and used to measure angular heights of the sun and stars occurred after 1484 when King John III of Portugal appointed a commission of mathematicians to refine methods of determining latitude at sea.
The mariner’s astrolabe was replaced with the Jacob’s staff or cross staff for navigation early in the 1500s, although it had been invented in the fourteenth century for use on land. It is usually made of wood with perpendicular bars called vanes that slide up and down a central staff to measure angles between two distant points. John Davis invented the back-staff, also called Davis quadrant and English quadrant, around 1595 as an improvement to the astrolabe, cross staff and quadrant for celestial navigation. It was operated with the user’s back to the sun and provided much more accurate readings. The back-staff is a long crossed triangle with a 60° arc at one end and a 30° arc at the other. Moveable peep sights (alidade) slide along the arcs to line up the horizon with a shadow cast by the sun across a horizontal bar on the front sight. The angular height of the sun is then determined by adding the readings on the two arcs and look up tables provide the ship’s latitude.
The octant, also called the ‘Hadley quadrant’, was invented by John Hadley in 1730. They have a 45° arc but can measure 90°. They operate similarly to the back-staff, but use a mirror to reflect the sun through colored filters to line up the horizon. Like the reflecting circle and later sextant, light reflected from an object is displaced by twice that angle, so even though octants were fitted with an arc of only one-eighth of a circle, they gave an effective reading of twice that or 45°, same as an quadrant. So the ancient quadrant lived on. Octants were made of wood, often mahogany and ebony in the late 1700s with brass and ivory fittings and silvered scales. As testimony to their enduring value less elegant models were still being certified for marine navigation as late as 1925.
The sextant was conceptualised in the late 1750s based on the contemporary invention of the reflecting circle even though it resembles an octant. The earlier ones were large, heavy and cumbersome. They employ a relatively small 60-degree arc and refined methods of marking degrees on the scale lead to hand-held versions that became rapidly popular by the end of the century. The sextant with its superior accuracy allowed crude estimates of longitude based on the ‘lunar distance’ method (distance of certain stars from the moon) that was discovered in 1767. The American military adapted sextants to aircraft in 1922. They were designed for reference to the broad and steep angle between the aircraft and horizon. Some were attached to gyroscopes and called gyro-sextants. In 1933 an electrically driven gyro-octant was tested. Sextants are still made and sold as backup navigation devises, and seamen are still instructed in their use.
Standards were established for clocks and compasses by the mid-1700s and chronometers, clocks that keep time at some reference position, usually homeport, were carried aboard most ships by the end of the eighteenth century. If time at a reference longitude were known, navigators could take ‘lunar distance’ measurements from key stars and use look up tables to determine longitude.
The station pointer is a triple-armed circular protractor (instruments vary from about 5 to 12 inches in diameter) originally made of brass that is placed over a map or chart to determine a ship’s position (or on land, the user’s location) relative to three distant points that are on the map and visible from sea.
Other instruments of navigation include ocean depth gauges or depth sounders which were replaced by echo-sounding and sonar in the 1920s, ships logs, navigational charts, traverse boards or helmsman’s boards which record a ship’s course when it was tracking into the wind and was used with a compass and ship’s log. Traverse boards were in use at least by the sixteenth century. Ancient techniques that were used to estimate a ships speed employed ropes with a log or board tied to the end, hence the origin of ‘log’ or ‘logging’, log-lines or ropes with knots tied at 6-foot intervals (fathoms), were used. The log would be tossed off the ship at the bow and the seconds counted or recorded by the time it reached the stern and the length of rope or number of knots reeled out provided the figures for calculating speed. Recent ship speedometers from the early 1900s use small foot-long torpedos with spiral fins attached to a rope with a speed gauge.
Planetaria, Globes & Maps
To learn more about antique instruments of Astronomy and Geography order Opticalia-Antiques’ 500-page illustrated Reference Guide to Antique Instruments of Science, Technology and Discovery. For ordering info click*
This short reference on the history of scientific instruments is a short cut to the subjects covered in the comprehensive Reference Guide Opticalia Antiques is publishing in 2005. This link is intended for a quick review of the various categories in the on-line catalogue. The Guide has sections on Astronomy and Geography where you will find much more extensive information and descriptions of instruments of these scientific disciplines.
Since early historic man was preoccupied around the world with the movement of the sun, moon and planets which many believed were deities, it is no wonder that the earliest instruments for documentation of observations would deal with astronomy. One of the earliest of scientific instruments are forms of planetaria or celestial models. Written references indicate that Plato’s Academy likely had a planetary model in the fourth century BCE Ptolemy refers to a planetary model in the second century CE, which is taken by some historians as the original armillary sphere. The word ‘armillary’ means ‘ring’ in Latin. The armillary sphere is composed of metal rings outlining an imaginary sphere and mounted on a stand. The rings represent great circles of the celestial sphere and are oriented either to the zodiac or the celestial equator. The equatorium is a flat disc based on the epicyclic theory of Ptolemy that places all planet orbits in the ecliptic plane. They are known as far back as the eleventh century. Equitoria were usually made of paper or cardboard but some were made of brass and elaborately decorated.
In 1709, clockmakers Tompion and Graham made a planetarium, eventually labeled an orrery in which the earth, moon and sun were attached to metal plates that revolved when the user turned a hand crank. It was copied by John Rowley in 1716 in ornate design for Charles Boyle, the fourth Earl of Orrery, hence its name. A model that represents the earth and moon revolving around the sun is known as a tellurium and is usually operated by a hand crank. A cometarium is a planetaria model showing the orbit of a comet around the sun. The torquetum was invented around the end of the thirteenth century in order to determine the position of stars, planets and comets and to relocate them at will. It was a plotting and sighting instrument similar in purpose to the astrolabe and like the astrolabe without benefit of the yet to be invented telescope.
Globes have been made to represent the earth, moon, planets and the night sky or celestial dome. Celestial globes are by far the oldest of globes and continued to outnumber terrestrial globes until the 1500s after which the two were usually sold as paired sets. This practice continued into the 1800s. Pocket globes were popular during the 1600s and 1700s and usually had an earth globe encased in an outer hinged shell the inside of which contained the celestial sphere in concave projection and thus realistic in appearance. The oldest known surviving celestial globe is the decorative 25-inch Farnese believed to date to about 200-300 CE.
The familiar planetary globe of the earth is known from the times of Copernicus in the sixteenth century and the earliest earth globe believed to have been invented around 1495 was untimely in that it excluded the new found western hemisphere. Earth globes typically depict the oceans and land masses with their geopolitical and country boundaries. They were used apparently infrequently for navigation through the 1600s. Navigational globes, due to their fragility, awkwardness, expense and general lack of detail, understandably gave way to flat maps. Globes and maps may also be printed with variations in geography, terrain type, climate, rock lithology, ocean currents, crustal plates, animal habitat and any other geo-referenced data suitable to the ‘small scale’.
Maps are not usually included with scientific instruments. But inasmuch as they vary from globes only by means of projection; are used to record the spatial distribution of scientific information; and are indispensable in exploration, navigation and discovery, we have decided to include them. Maps vary in the composition of the paper, printing method and type of projection as well as the information they contain. They can be broadly dated by country borders and other geopolitical designations, accuracy of coastlines, lettering and type style, ink used, composition of paper, place names and wording.
The oldest known map is of an Egyptian gold mine drawn on papyrus around 1320 BCE The oldest known map of the world is from fifth century BCE Babylon and inscribed on a clay tablet. Maps look different depending on the type of map projection used, which is discussed in more detail in the Reference Guide. Maps were hand drawn until the Chinese first started printing maps around 1150 CE Prior to the 1700s most maps were printed on hand made paper often composed of coarse fibers.
Laboratory & Analytical
To learn more about antique Laboratory and Analytical Instruments order Opticalia-Antiques’ 500-page illustrated Reference Guide to Antique Instruments of Science, Technology and Discovery. For ordering info click*
Instruments used primarily in analysis and experimentation, especially in the laboratory, are at the heart of scientific investigation and research. Scientific instruments of this type are the most numerous and total in the thousands. Laboratory instruments deal chiefly with the chemical and physical properties of liquids, gases and solids but we include as well those used in the outdoor ‘laboratory’ to study nature. Only a few of this important and extensive category of scientific instruments can be mentioned in this short review. In the Reference Guide we break out instruments of Botany and Zoology, Geology and Geophysics, Chemistry and Analytical and Physics into separate categories.
There are many devices used in wet chemical study and analysis, including burettes, pipettes, test tubes, flasks, glass tubing, distillation vessels, chromatograph columns and many other types of glassware and glass apparatus. Many containers are graduated for volume or capacity measures in fluid ounces, grams, grains, pints, cubic cm, fluid drachms and other units of measure. The pestle and mortar, the pre-eminent laboratory symbol, has been around since the Stone Age for grinding grain. The more recent and more conveniently collectable pestle and mortar is usually a matched pair made of bronze, brass, pewter, agate, serpentine, jade, porcelain or iron and they are still made today, little changed, for practical laboratory applications.
To separate compounds of one type from another electrophoresis cells were developed as early as 1807 by Alexander Reuss using glass tubes and a voltaic pile (battery). Manometers are simply graduated ‘U’ shaped water filled tubes usually with an intake valve or horizontal bend at the top of one limb such that when pressure is applied into the tube the other limb registers the magnitude by rising. The thermometer is one of the most important and widely applied laboratory devices. A thermometer that measures temperatures above 500 degrees Celsius is generally considered a pyrometer. The spectroscope pyrometer is a type of spectrometer with a collimeter the user points at a furnace while looking through the eyepiece then relates the spectrum to temperature.
Hydrometers are buoyancy devices used to determine the specific gravity of a fluid. The Sykes hydrometer received legislative approval in England in 1816 and remained the legal standard until 1907 but was made and used in the wine and spirits industries to the mid-twentieth century. Typically, hollow bulbs made of brass with an attached rod for holding weights, hydrometers often come in wood boxes with brass or ivory backed thermometers, glass flasks, scales and magnifiers. Some hydrometers are simply glass tubes with a weighted bulb of mercury or lead shot and a graduated stem that sinks up to a mark that indicates the fluid’s density.
Fluid viscosity is measured with a viscometer which reacts to the resistance of a fluid to flow which is temperature dependent. The orifice viscometer invented in 1885 simply measures the time it takes for a fluid to flow out of a cup with a hole in the bottom. The acidity of a solution or its pH can be determined with an acidimeter or pH meter, invented in 1934 by Arnold Beckman. It’s a compact, portable device with a voltmeter and ammeter to measure the current.
Analysing solutions and fluids by color comparison has been a long applied laboratory technique. Early colorimeters relied on visual comparison with known concentrations of dissolved solute. Thus gave only a qualitative result. In the 1860s colorimeters were invented to compare colors ‘quantitatively’. The blowpipe has been called the ‘stethoscope’ of the nineteenth century chemist. It was the most prominent laboratory apparatus in the field of chemistry for 100 years from 1760 to 1860 and was still offered by manufacturers in the early to mid-1900s. It’s a simple tube of brass or silver about 8 inches long with a small orifice at one end and a mouthpiece at the other through which the user could blow a concentrated stream of air. The air was directed through a flame onto a powdered sample and the color produced observed for qualitative chemical analysis. Due to the development of photoelectric cells sensitive to the visible light spectrum, color comparison gave way to more quantitative instrumentation like the absorptiometer invented in 1936 and the polarograph, one of the first automatic analytical devices, invented in 1922.
The color spectra of visible light are also used for analysis. With a laboratory spectroscope the elements in the flame of a burned sample cast a spectrum through a collimator and prism that can be viewed and measured by an eyepiece micrometer to determine composition. Large astronomical spectrometers for analysing composition of stars date to the 1870s. The photometer measures the brightness or intensity of light on an illuminated surface. The spectrophotometer measures the intensity of light of a narrow waveband of the spectrum by combining the capabilities of the photometer and the spectroscope. A pocket-sized refractometer, developed in the 1870s, consists of a wedge shaped metal housing that holds the sample. Refraction of light rays are observed at minimum deviation through a prism in order to determine the refractive index of the sample. The refracted rays impinge on a scale. Interferometers separate wave bands of light and other electromagnetic energy wavebands into separate beams for a variety of laboratory purposes. To study the intensity of visible or ultraviolet light, chemists invented the actinometer or dosiometer around 1790 which allows measurement of the reaction rate of a photochemically sensitive substance.
Polarimeters came into use around 1800 to allow observation of the interaction of an optically active substance with polarized light. The instrument looks like a segmented telescope mounted on a stand. Polarizing prisms are mounted in line at the front and at the eyepiece (analyser) with a space in between for inserting a metal observation tube with the test sample. By rotating the eyepiece polarizer the extinction or point where no light is transmitted can be determined and its variation in degrees adjusted on the dial and related to composition. The polarimeter helped direct development of the polarizing microscope for analysis of rocks and minerals in the 1830s. A specialized polarimeter called the saccharimeter was widely used to determine the amount of sugar in solution in the 1920s.
The radiometer is an elegant demonstration device invented by William Crookes in 1873 that responds to light radiation as well as other regions of the electromagnetic spectrum. It is nothing more than a philosophical instrument of high standing though late in the development record of that category of antique scientific instruments. It is an evacuated glass bulb with a delicate flywheel of four vanes that pivots on a thin metal post. Typically one side of the vanes is painted black the other silver or white. The vane turns when illuminated by visible and infrared light with the light side leading. The reason for the observation has been debated ever since. I have my own theory.
In the 1920s, due to the availability of photoelectric cells sensitive to the visible light spectrum, color comparison began to rely more on quantitative instrumentation. This new breed of photoelectric colorimeter, which could be automated, proliferated in the 1930s and one of the more successful was the Hilger-Spekker absorptiometer of 1936, which became widely used in metallurgical analysis. A polarograph is one of the first automatic analytical devises. It was created in 1922 by Jaroslav Heyrovsky, who received the Nobel Prize in chemistry for his invention. The instrument analyses for metals to an accuracy of 1 to 10 ppb. It is a simple electric and photographic device with a small electric motor, a galvanometer and potentiometer that drips mercury droplets from a glass tube at an electrode to produce current-potential curves or polarograms on photo-sensitive paper attached to a rotating drum. It can identify and quantify thirty different metals.
Assay equipment involves apparatus and devices related to analysing rock samples for precious metals like gold and silver. Equipment in assay labs will include crushers, pulverizers, crucibles, bone-ash and magnesia cupels, cupel moulds, lead presses and plugs for sealing sample bags, steel stamps for stamping bullion, furnaces, tongs, and precision balances.
Scintillometers or scintillation counters which are also known as Geiger counters, detect nuclear particles – beta and gamma rays – generated mostly by uranium and its radioactive by-products, potassium and thorium. A small pocket sized instrument similar to a scintillometer and called a spinthariscope was invented in 1903 by William Crookes as a demonstration device. It is a small triangular metal box with short tubes one for light the other a magnifying lens for viewing. Inside, a crystal of radium salt and a fluorescent zinc sulfide screen are mounted side by side. The viewer can observe radiation scintillations through the lens.
A variety of apparatus deal with air and gases. The air pump or vacuum pump was invented about 1647, and Robert Boyle exploited it in the 1660s to create macroscopic air vacuums for biological, chemical and engineering experiments. Most devises are hand-operated pumps, resembling bicycle pumps to draw air out of an inverted bell jar. The Bunsen absorptiometer was invented in 1855 by Robert Bunsen to study the effect of pressure on the solubility of gases and measure absorption coefficients. It consists of a graduated glass tube with a thermometer encased upright in a glass cylinder that can be shaken.
In the late 1700s instruments called eudiometers were developed to measure the ‘purity’ of the air. In this devise the test air or ambient environmental air is compared to air mixed with nitrous oxide over mercury or water and the volume change during combustion observed in graduated tubes. Although beset with controversy they were manufactured well into the nineteenth century. Nitrometers and gasvolumeters are specialized tubes and burettes for analysing nitrogen and soluble salts. The Kjeldahl apparatus for nitrogen analysis uses an arrangement of several flasks and burners on retort stands for digestion and distillation. The calcimeter measures carbon dioxide in compounds of calcium carbonate.
Like any other field, specialized instruments have been developed for botanical and zoological studies in the biology laboratory. The auxanometer was invented in 1843 by August Grisebach to monitor the growth rate of plants. He used a toothed wheel to mark branches, shoots and leaves and measured the displacement as the plant grew. The spherometer is a simple calliper developed in the 1870s to measure plant thickness. The osometer is used to measure the pressure on a membrane to study cell behavior, osmosis and ion transport in liquids. The porometer measures leaf permeability by determining rates of air flow by applying pressure across a leaf or rate of diffusion of a gas like water vapor or hydrogen into a leaf, important criteria in agricultural to assess crop condition and irrigation. Resistance porometers measure leaf resistance using pressure manometers.
Pressure bombs measure the potential of a plant to take in water. The bomb is a small, strong pressure vessel with a gauge. A severed leaf or branch sample is placed into the bomb so sap will appear as pressure is applied, which is then related to the water potential of the plant. The potometer is a simple botanical research invention of Julius von Sachs around 1875 that measures the rate of water intake by seedlings and cut shoots under variable environmental conditions like humidity, temperature, light and wind. Plant physiologists can measure the water potential of soil or plants with a psychrometer, consisting of an airtight chamber to hold the sample, a thin wire thermocouple to measure temperature and a micro-voltmeter that measures in water potential units. A clinostat is comprised of clockworks within a dust and moisture proof case geared to a rod on which a plate with potted plants can be placed for timed rotation to allow studies related to environmental vectors like sunlight.
The specific gravity of minerals, rocks and other solids is measured with a hydrostatic balance, a scale that weighs objects in air, then submerged in water, the ratio of which is its specific gravity, water, having a specific gravity of 1, being the standard for comparison. The goniometer is used chiefly in mineralogy for measuring angles between crystal faces in order to deduce the crystallographic properties of minerals one of their defining properties and classification features. The first goniometer was the contact goniometer invented by Jean Rome de I’Isle in 1873. It consists of a simple small hand held half circle open-frame protractor with two pivoting indicator bars linked to each other and the base of the protractor with an adjustable screw through longitudinal grooves down the middle. They are rotated and slid against one another in order to measure the angle between the faces of a crystal. Remarkably the instrument is still manufactured today and for practical use. Quarter circle and full circle goniometers were also produced. More complex and precise goniometers soon followed that were mounted to stationary stands and incorporated mirrors, magnifying glasses and microscopes. In 1809, William Wollaston invented the reflecting goniometer which could analyse the crystal form of very small samples, which lead immediately to extensive documentation of mineral structures and identification of new mineral species.
Ultraviolet lamps are used to stimulate luminescence in florescent minerals or in some critters like scorpions, for example. The instrument is used for purposes of identification and for demonstration of light and electromagnetic radiation. They typically operate at two frequencies – long and short wavelengths – to which some minerals are sensitive to one or the other.
Moh’s hardness scale, devised in 1824, is used primarily by geologists in the field and lab since hardness is one of the characterizing properties of minerals. It is a simple relational scale from 1 to 10 that compares the hardness of a mineral to a standard by a scratch test. The standards are are set of simple small pencils with the mineral standards attached at the ends. Hardness testers are used primarily in metallurgy and engineering. They are typically bench top devises. Portable weighted pendulums, designed in the early twentieth century as impact testers, were used to test the impact resistance of metal alloy plates. The Melting point apparatus determines the melting point of solid compounds and was first devised in 1810 to characterize and identify organic compounds and their purity.
Instruments that measure the gravity, magnetic and electrical properties of the earth fall into the field of geophysics and are used in civil engineering and earth science. They are applied extensively in exploration for hydrocarbons and minerals, geotechnical investigations connected with construction, and to monitor potential environmental hazards like earthquake faults or volcanoes.
Early discovery of the earth’s conductive properties by Gray and Wheler in 1746 lead to the self-potential instrument to measure resistivity of rock units. Magnetometers are used to measure the magnetic properties of rock types in the subsurface. Measurements were originally made in 1723 with a dip needle by observing the oscillations of a compass needle and strength of the local magnetic field on its inclination in the vertical toward the ground, rather than declination in the horizontal or azimuth. The electronically configured fluxgate magnetometer, invented around 1940 to detect submarines was largely replaced during the 1970s by the proton precession magnetometer, which uses the precession of spinning protons (Hydrogen atoms) in a hydrocarbon fluid to measure magnetic intensity to high precision.
Torsion balances have served as gravitometers since 1888 to measure gravity by suspending a ‘test’ mass from a spring and measuring the displacement. A torsion balance that measured the rotation of a quartz thread with a weight attached using a goniometer was invented in 1898. The seismometer detects and records tremors, earthquakes or man-induced vibrations. Most devises use a mass attached to a spring or pendulum and a recorder to produce seismographs. A graph of the return or reflected vibrations gives a map of the density of rocks in the subsurface that relates to the rock stratigraphy.
The ‘pocket penetrometer’ is a 5in.long metal rod graduated in kgs, with a cone at the bottom, a spring around the shaft, and a handle for pressing the cone into the ground to test hardness. The related but more sophisticated pressurimeter is a long metal probe with membranes inside that is lowered down drill holes on cables. Once pressurized, results are measured on pressure gauges. A piezometer measures pore pressure within the voids of rock and soil in earthen dams, road embankments, mines and construction sites.
Models and display collections are used in laboratories for demonstration and teaching. For example, sets of crystallographic models in pear wood, hardwood or glass date back to the nineteenth century and models of geometric shapes go back even further
To learn much more about antique laboratory and analytical instruments and tools, order Opticalia-Antiques’ 300-page illustrated Reference Guide to Antique Instruments of Science, Technology and Discovery. For ordering info click*