The earliest barometers were called weatherglasses or thunderglasses, because they could predict rain. Filled with water, the water column in the long spout of an otherwise sealed glass bulb, rises in response to low barometric pressure, thus predicting potential rain. The Kew marine barometer was developed following an international conference on meteorology held in Brussels in 1853. It is a cistern-type stick barometer encased in a brass cylinder attached to gimballed brackets for mounting to ship cabin walls or posts. The wheel barometer has a long history but became popular in the mid-1700s. Mercury in a ‘U shaped glass tube of a wheel barometer, reacting to atmospheric pressure, moves a silk string looped to a pulley wheel that adjusts the indicator needle on a graduated dial. The wheel barometer became widely popular in the domestic market and was often artistically designed with ornately carved frames and ivory and mother-of-pearl inlay. Barographs and thermographs work on the principle of expansion or contraction of a coil, chamber, spring or wire in response to changes in barometric pressure and temperature, respectively. An arm with a pen attached records continual change on graph paper. Cloud cover and morphology are studied with instruments like the nephelescope, invented in 1835, and the cloud chamber, invented in 1895.

The word, ‘barometer’ derives from the Greek, ‘baros’, which means ‘weight’. Observations in the 16th Century and experiments by Galileo in the early 17th century with water as the recording medium were precursors of barometers. Mercury was first used in a barometric experiment in 1643 by Vincenzio Viviani in collaboration with a student of Galileo’s, Evangelista Torrecelli. They filled a thin glass tube with mercury, placed a finger over one end and submerged the other end into a pan of mercury. When the finger was removed, the mercury in the tube settled to a lower height in response to atmospheric pressure. The earliest mercury barometers are called, collectively, cistern or stick barometers, which are simply long glass tubes with the bottoms submerged in a cup filled with mercury. To improve precision, the angle tube barometer, also called the yardarm, diagonal, or sign post type was invented in 1670. The tube on this instrument extended 36 inches at a slight angle to the horizontal, thus a 3 inch vertical variation in the mercury level was recorded over a much greater vector, horizontally. The ‘aneroid’ was invented in 1843, revolutionizing barometer instrumentation. Lucien Vidie created a metallic pressure indicator in 1843 he called an ‘aneroid’, which means ‘dry’ or ‘without liquid', and effectively revolutionized the barometer. For the sensitive pressure detector he used a sealed brass box with a corrugated diaphragm supported by helical springs. A popular pocket-sized version, only 2.5 inches in diameter, was developed by Negretti & Zambra in 1860, and a type of aneroid barometer that graphs changes in barometric pressure on paper - the barograph - was developed about the same time.

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.