LATERAL C-LIMB MICROSCOPE BY R. KRUGELSTEIN
YEAR: circa 1885
MAKER: R. KRUGELSTEIN, BERLIN (A)
SERIAL NUMBER: 1715
MODEL: --?--
DESCRIPTION:
The all lacquered-brass instrument is unsigned but obviously by Krugelstein as is clear from many features of the instrument. The microscope arises on an I-shaped pillar from a typical horseshoe-shaped
continental foot. The serial number is on the upper plate of the parallel linkage mechanism as shown in the
image to the left. This contrasts with the other Krugelstein Microscope
in this collection where the serial number is on the bottom plate and there is a signature on the top plate. The limb can incline from the vertical to the
horizontal.
The substage apparatus consists of a rotating conical wheel of apertures attached to the underside of the stage by a screw. The 'lateral-C' limb above
the stage allows the fine focus knob to project downward, acting on the
parallel linkage fine focus mechanism above. Coarse focus is by
straight rack and pinion in contrast to the later Krugelstein microscope in this collection which has diagonal rack and spiral pinion focusing.
Accessories include the two different
condenser fittings, three eyepieces (numbered 1, 3, and 4), and four original objectives (numbered 3,4,7 and 10) supplied in a separate little box. The box appears to be covered in fishskin with purple velvet over cotton lining the lid and the wooden fitting within apparently made of walnut. There is a working catch to hold it closed. These objectives, like others supplied by Krugelstein, are of smaller diameter than the RMS standard, and these in particular are female threaded rather than the customary male threads. The other Krugelstein microscope in this collection has male-threaded (but still non-RMS sized) objectives. The brass optical tube is fitted with a brass drawtube. The gimbaled substage
double-sided plane and concave mirror is on a swinging tailpiece, allowing oblique illumination. The original fruitwood case
features brown velvet cloth cushions over the wood fittings. There is a compartment under the
microscope which is empty.
Another very similar model was sold on Ebay in 2014, but had a triple nosepiece and did not have an inclination joint. Because of the triple nosepiece, it had male threaded, rather than female threaded objectives.
HISTORY RELATING TO R KRUGELSTEIN AND FEATURES OF THIS MICROSCOPE
Krugelstein is one of the lesser-known German microscope
makers of the late 19th and early 20th century from about 1875 to the
early 1900's. Stands by this firm are rather uncommon. There are no
Krugelstein microscopes in the Billings Collection, and most private
collectors do not seem to have one. Krugelstein microscopes are known
for the downward facing fine focus control inside a C-shaped
limb above the stage that curves to the side rather than to
the back, as in most microscopes.
The downward pointing fine focus is found under the limb
above the stage in microscopes by many makers, including Baker (Nelson
Model), Sidle (ACME No. 4), and others, but only in Krugelstein models
does the limb form a lateral curve.
The parallel linkage fine focus mechanism was apparently
invented by Gundlach and/or the Seiberts when they were all working
together; it was used by Seibert for many years after Gundlach left for
the United States. This type of fine focus was also used by Lietz in
Germany and even by Walter Bulloch in the U.S.A. on the Bastin-Bulloch
microscope. In the example by Seibert
in this collection, the fine focus knob is under
the stage and the pillar is a
lateral-facing C., as opposed to the lateral-C shaped limb
above the stage found on Krugelstein stands. Many other German makers
used the lateral C form of pillar this way, but apparently only
Krugelstein used a lateral C form of Limb.