This large microscope has a typical bar-limb construction
with rack and pinion focusing. It is based on a design
introduced by Andrew Ross introduced in 1843. It measures 20-inches
tall inclined as shown in the photos. The rack and
pinion focusing sub-stage has centering adjustments. Among
the remaining accessories are three objectives
(1, 1 1/2, and 1/4-inch) with canisters,
a Lieberkuhn reflector for the 1-inch objective with canister,
two eyepieces, a stage forceps, a live-box, and a hand forceps.
John Davis (1811-1873)
was a member of a family of Jewish descent long
involved in instrument making, originally in Leeds.
John began to work on his own where he set
up in business in Derby c. 1831 moving to
22 Iron Gate in 1835, where the firm remained until
1865 when they moved to a new premises nearby in Amen
Alley. Davis`s early products were what would be
expected from an optician of the period, but by the
1840s he began to specialize in mining, surveying,
and other industrial instruments in which the company
still produces. Microscopes by the firm are uncommon.
See a more complete history of the firm here and here.