Many of the accessories are made of hard rubber.
This is a characteristic of the earliest B&L instruments. This
microscope was designed by Ernst Gundlach while employed by Bausch
& Lomb. The low serial number (76), which is stamped on
the inside bottom of the case, indicates that this instrument was
manufactured in the first year of production.
The leading idea in the
construction of this microscope was to furnish at a
moderate price an instrument suitable to the
application of a variety of accessories, desirable in
many operations of the microscope, thereby enabling
the operator to perform a variety of microscopical
work for which our lower priced instruments are
It is provided with a
heavy brass foot, highly finished, inlaid with three
soft rubber pads at the under surface, and two solid
brass pillars supporting axis for inclination of the
body. Two strong screws with milled heads, placed at
the ends of the axis, serve to tighten or loosen the
connections by means of which the arm can be made to
move with more or less ease.
Coarse adjustment by
rack and pinion, moving a long prismatic slide
accurately fitted, attached to the body, and arranged
for compensation of wear. Fine adjustment by
micrometer screw, with milled head, silvered and
graduated, acting upon our patent movement described
Glass stage with slide
holder similar to that described with microscope No.
540, but is of larger dimensions, circular in form
not shown in cuts, and fitted to receive the
hemispherical immersion condenser. In this stage we
gain thinness, while still maintaining its
stability.The slide carrier moves in any direction,
and also revolves.
Substage and mirrors
(plane and concave) are fastened to swinging mirror
bar, the axis of which is fixed in the plane of the
object, thereby permitting the accessories and mirror
to swing concentrically around the object. The mirror
may be brought to any obliquity and swung above the
stage for the illumination of opaque objects. The
mirror as well as the substage, can be moved on the
mirror bar to and from the object, and both can be
removed altogether, in an improved manner not shown
in the illustration.
The substage ring
receives the revolving diaphragm, condenser, etc.,
and auxiliary ring with internal society screw, which
accompanies the instrument, and to which objectives
and other auxiliaries may be fitted.
The history of the
development of this microscope is described in the