Terrestrial 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. These compasses are usually marked either from 0-360° azimuth or in quadrants from 0-90° with east and west reversed so the needle registers the direction of the pointer. The first recorded use of compasses in surveying was during the early 1500s when they were mounted first to astrolabes then circumferentors and graphometers. They remained a mainstay of surveying through the twentieth century. Geologic compasses are typically fitted with a vertical angle indicator needle fixed at the center of the compass card with the needle, so it rotates by gravity to indicate vertical angle when a flat side of the compass case is placed against an inclined plane.The prismatic compass was designed in 1812. It is a surveying compass that has a right angle magnifying prism attached to the back site with which to read fractions of a degree from the scale. Compasses have been made as wrist straps, mounted on walking cane handles and map chartometers, and made as watch swabs, brooches and pins.