Botanical microscope in case, C 1790
An unsigned Botanical Microscope in original case, C 1790. The body consists of a single square pillar that supports the sliding stage, for focusing, and is topped by a brass cantilever that holds three objectives. Each of the objectives is mounted on an arm that allows it to be swung into place above the sample. From one to all three objectives may be used at one time. The stage consists of a thick brass top piece and a thinner spring stage below. Spaces between the two pieces allow a sample slide to be slipped in and maintained in place by friction. Focusing is accomplished by sliding the stage along the main support pillar. The pillar fits into a square base that itself is screwed to a brass base. The pillar is held in position by a pin. Also mounted on the pilar is the illuminating original mirror. It has only one parabolic reflecting surface with some damages but working. The microscope may be stored in a rectangular carrying case. The complete instrument is 11.5 cm high. Accessories include three bone slides, a stage forceps, and a separate brass forcep. Imaging is good for a field botanical microscope, and ranges from approximately 3x to 15x. measurements mahogany box 13 x 9 x 5 cm high.
The Botanical Microscope was derived from the earlier “Aquatic Microscope”. It differs in its focusing mechanism. The aquatic microscope used a rack & pinion focusing mechanism to move the single objective without moving, and subsequently disturbing, aquatic life that was being observed.