Dissecting microscope by Dollond, 1/4 19th C.

Signed: Dollond LONDON
Box base 21 x 14,5 x 4,8 cm; overall height c. 17,3 cm

The pillar screws into a boss set in the lid of the mahogany box. The limb slots into a housing that pins at the top of the pillar; this permits a circular as well a back and forward movement. The limb has a threaded aperture at the end for the objective. This is raised and lowered by rackwork, with the extension tube fitting the pillar, operated by a millead-head. The signed circular stage dovetails into a bracket in the pillar; it has a shaped ear for an accessory. A concave mirror pins near the base of the pillar.There are five objectives: two with lieberkuhn; one with a large lens and a threaded brass cap; one from another instrument. There is also the mounting for stage forceps, a sprung slider holder that fits into the stage, and a turned ivory canister for slide covers and retaining rings. The case has some blue plush-lining.

The design of this instrument originated with John Ellis (1710-1776), an English naturalist who was at one time the Agent for West Florida. The intention was to have a movement to the objective so that it was easy to follow the activity of small water creatures held by a watch-glass on the stage. The first model was made in 1752 for Ellis by John Cuff.