Single lens microscopes were widely used in the nineteenth century, especially in the field, even by scientists of the caliber of Robert Brown and Charles Darwin.
A brass column supports a lens, a moveable support for a specimen on a spike or on a slide, and a mirror to reflect light up from below for a transparent specimen.
Often, several lenses were available that could be interchanged or even combined for higher magnification. When not in use, everything could be folded up and stored in the box that also served as a base.
This model has an interesting pedigree. In 1855, the Society of Arts offered prizes to encourage the manufacture of good, economical microscopes. The 'student' model had to sell for 3 Guineas (£3/3/-) or less and the simpler 'school' model for half a guinea (10/6) or less. Field was awarded both prizes, and this is an example of the 'school' model.
The box appears to be made of a cheap fruit wood, and is held together by staples, rather than with dovetails. This reduced the cost of production and increased profit.
