Portable folding microscope with polarization. c. 1877
While this microscope
is unsigned by the maker, it has very strong
similarities to some folding microscopes made by
James Swift (& Son), London. Compare this
monocular microscope with a
signed binocular version that is also in this
collection. This type of portable folding microscope
was first introduced in the 1878 Swift catalog of
microscopes. The microscope was offered either as a
monocular or Wenham binocular. It is described in the
catalog as follows:
"This Microscope is
so constructed that it can be readily set up for
immediate use without the necessity of having to
screw any part or parts together before using, a
defect so often complained of in most portable
microscopes. The whole of its joints and working
parts are made to compensate for wear and tear, and
when ready for use, as shown in Fig. 1, is remarkably
firm and steady under high magnifying power. It has
sufficient coarse adjustment to work with the 5-inch
objective. Lever fine adjustment with central lift.
The stage is very large, and has an adjustable
object-carrier, working upon glass bearings for
smoothness of action, whereby an object can readily
be adjusted under a one-sixteenth
objective."
The microscope folds
and fits snuggly within the mahogany case measuring
10 x 5 x 3 inches. It is supplied with one unsigned
objective, two eyepieces numbered 1 and 3, a stage or
limb mounting bullseye condenser, and a stage
forceps. The main focus utilizes a straight rack and
pinion and the fine focus uses a nosepiece short
lever mechanism operated by a micrometer screw. Built
into the bottom of the tube is an an analyzing Nicol
prism in a sliding mount. The sub-stage has a
polarizing prism in a rotating mount. The upper
portion of the sub-stage fitting has a mounting with
a Society Screw that will allow an objective to be
fitted to serve as a condenser.
Another signed example of this
microscope has recently sold at auction. Examples of this microscope are known which do not have the polarizing attachments as found on the microscope shown on this page.