Instruments, Polariscopes Hand-held polariscope, 19th century

Instruments, Polariscopes Hand-held polariscope, 19th century. (Polariscope de demonstration, pour montrer et observer les differences de structure entre des echantillons de mineraux vus a travers une lumiere polarisante) This hand-held polariscope is a demonstration device to show how thin sections of different minerals look when viewed in polarised light. A selection of seven mineral samples are mounted on a rotating wheel so that each can be examined using an eyepiece fitted with a polarising material such as Iceland spar. As each sample is passed in front of the polarising eyepiece the lights intensity will vary greatly indicating different types of crystal structure. Made from turned rosewood the sample wheel carries labels for each mineral. The samples are viewed in turn through a slotted opening in the handle of the instrument. ©SSPL/Science Museum