Bausch & Lomb Optical Co., Rochester and New York City, #16221
The final version of the Professional Model microscope, c. 1894
The calibrated stage is
capable of full rotation and has centering adjustments.
The substage has independent calibrated movements of
the mirror and condenser arms.
The following was extracted from the 1892 B&L catalog:
PROFESSIONAL MICROSCOPE -
This instrument may be considered as the highest attainment in microscopical construction,
in design, solidity and practical utility of the various parts. It is entirely constructed
of brass and bronze. The base is unusually large and heavy. To its upper surface is
fastened a revolvable plate graduated and provided with index, to which is attached
two pillars. The arm is fitted to pillars by joint for inclination with steel axis.
Coarse adjustment is by rack and pinion with large milled heads. The micrometer
screw acting on fine adjustment is graduated to hundred parts and provided with
index finger. Main tube has draw-tube working in cloth lining. Tubes when contracted
are of the long standard. Mirror and sub-stage bars are separate and have independent
movements working on an axis in the plane of the stage; both are graduated to degrees.
Mirrors are plane and concave, of unusual large size and adjustable on mirror-bar.
The sub-stage consists of the entire attachment No. 1684, and has a long adjustment
by rack and pinion. The stage is revolving, graduated to degrees and provided with
vernier. It has spring clips and centering adjustment. Graduations are all silvered.
Eyepieces are the Huyghenian, objectives of Series II, unless otherwise stated.
The microscope is equipped with the B&L patented (1877) glass stage
and slide carrier, which is described in The Journal of
the Royal Microscopical Society, 1882 as follows:
Bausch and Lomb
Optical Co.'s Glass Stage and Slide- carrier.
This (Fig. 128) is intended as a substitute for
the mechanical stage to a certain extent. It
consists of a polished plate of glass, incased in
a brass ring, which clamps on the circular stage.
The slide-carrier, which moves on it, consists of
a light metallic plate, and has protruding from
its lower surface four small points; at its two
ends are prolongations, which are bent downward
and inward, and, acting as springs, press against
the lower surface of the glass. As the contact
between glass stage and slide- carrier is only in
these six points, friction is reduced to a
minimum, and the action of the latter, although
firm, is smooth and steady. It is claimed that it
enables work to be done with far more facility
than in the ordinary brass stage, where the
entire surface of the slide bears on it, and that
it is altogether more agreeable. The slide-
carrier is provided at each end with small milled
heads for manipulation, and has spring clips and
a stop for Maltwood finder.
Among the accessories are
three B&L objectives with canisters marked 2/3,
1/6, and 1/12 water immersion, three eyepieces marked
2, 1, and 1/2-inch, a triple nosepiece, an alternate
quick change nosepiece, and a B&L safety nosepiece.
The substage consists of a rack and pinion
focusing Abbe condenser with iris diaphragm and
represents the final version of the Bausch & Lomb
Professional Model microscope. It primarily differs
from the earlier versions with respect to the shape
of the limb and the use of a similar fine adjustment
mechanism that was used with the contemporary B&L
continental style microscopes. This fine adjustment
mechanism was later patented in 1897. In addition,
the Abbe condenser used on this version of the
Professional model is similar to those that were used
with the continental model microscopes that were
manufactured at the time. Within a few years after
this microscope was made, the Professional Model was
discontinued; only the continental style microscopes
were then offered by the firm.