The lever located at the nosepiece moves the Wenham prism in and out of the optical path.
The accessories consist of six Grunow objectives (2, 1-1/2, 1, 2/3, 1/5 and 1/10 inch) each with brass canister, two pairs of oculars, analyzer prism (screws above the objective), substage polarizer, camera lucida, paraboloid condenser, and some adapters and aperature stops. Note that the objectives are in short mounts allowing them more effective when using the Wenham prism. The painted wood storage case with glass front and internal drawer was custom made for this microscope, but it is not the original case.
This microscope dates from around 1874. The Grunow brothers, Julius and William, emigrated from Germany to New York around 1849. They started in the scientific instrument business by first working for the optician Benjamin Pike of that city. By 1854, they began their own operation in New Haven CT where they concentrated on the production of microscopes. By 1864, they were back in New York. Some years later, the partnership ended. J. Grunow continued on to produce microscopes up to around 1892. The total output of the Grunows was limited in comparison to some other contemporary firms; on the basis of the observed serial numbers, they manufactured just over one thousand microscopes in total.
