The main focus utilized
with this microscope operates on the stage by rack and
pinion. The tube remains stationary and has a fine
adjustment operated by the milled knob attached to the
tube which moves the nosepiece.
Another microscope by the same makers with a
similar focusing arrangement can be found elsewhere on
this website.
The firm was established
around 1840 by the purchase of the instrument business
of Edward Palmer, London. Instruments by this firm had
the signature Horne, Thornthwaite, & Wood, London
from c. 1840-1860 after which, the
instruments were signed Horne &
Thornthwaite, London (c. 1860-1880). By 1886 Wood
rejoined the firm.
See
this extensive essay on the firm
