This simple microscope is of the type promoted by the British naturalist John Ellis (1707-1776). It became a popular design and was manufactured in various forms by a number of British and Continental makers. This outfit is supplied with two objectives with Lieberkuhn, a high power objective, an eye shade, a stage forceps, a glass insert for aqueous specimens, and a Bonnani spring stage for use with the ivory sliders. This particular version of the aquatic microscope focuses by rack and pinion. The mirror is single sided.
The use of the word “aquatic” to describe these types of microscopes is due to the fact that the stage is large and the horizontal arm holding the objective can slide in and out and also swivel in an arc making it ideal for the observation of live aquatic organisms. A microscope that functions like this is said to have an “aquatic motion”. The microscope is shown fitted with the Bonnani spring stage, but it can also accommodate the glass insert which would be used for the observation of specimens in water.