Maker's Name: 
E. Leitz, Wetzlar
Where made: 
circa 1900
16 × 13 × 36 cm

This microscope is specially constructed for the study of minerals and their identification. The Ernst Leitz Company, founded originally in 1849 in Wetzlar as The Optical Institute with a focus in telescope manufacture, became world renowned for their microscopes and optical products. In 1865 Ernst Leitz was hired as an engineer in and 1869 he took over the company, renaming it The Optical Institute of Ernst Leitz. In the first 20 years under Leitz, the company produced 15,000 microscopes and in the early 20th century production expanded to include film projectors and binoculars.

The Ernst Leitz company was a pioneer in the field of polarised microscopy and the use of polarised light in microscopes. In 1885 the company introduced the Polarizing Leitz microscope. The microscope in the case is a later example of their polarizing microscopes.

This collection piece consists of a brass tube with two objective lenses, with a model No. 105906. Like the previous microscope on our tour, the Zeiss Compound Monocular microscope, the lenses are interchangeable. Polarising plates can be slid into the optical path in order to analyse the polarisation of the light transmitted by the sample. Underneath the rotating base is the light source and a Nicol prism, which allows the user to choose the polarization of the illuminating light. The substage Nicol prism, eyepiece, and one focussing handwheel are replacements fitted when the microscope was restored by Windsor Davies in 1990.

The polarising plates, inserted into the body tube of the microscope, are what allows detailed study of minerals. A sample can be placed on the rotating stage beneath the lenses. Each polarizing plate will only allow light of a specific orientation through and by rotating the base plate of the microscope and observing the light that exits the plates, the polarisation of light transmitted through the sample can be deduced. In the field of mineralogy knowledge of light polarisation, along with other observable characteristics such as colour, grain fracture and refractive index allow for a thorough assessment of geological substances. For example, geologist can identify types of minerals and their composition.

This item is part of the UQ Physics Museum Microscopes Tour
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