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Microscope Museum Collection of antique microscopes and other
scientific instruments |
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Microscope
153 (Ross;
Improved No. 2 ‘Standard’ microscope; c. 1905)
Andrew Ross founded his
business in 1830 and, like James Smith, collaborated with J.J. Lister, the
maker who invented a mathematical method of producing objectives which were
both achromatic and aplanatic. Ross's early instruments were constructed
initially in a fashion similar to the Jones-most-improved models, followed by
a construction similar to that of the 'Lister Limb' and he continued this
practice until the 1840's when he developed his version of the Bar-Limb, a
very stable design and from then on also supported his larger stands on the
classic Y-shaped foot with two upright supports. Early examples of the Ross
Bar-limb construction used a triangular bar, which was later replaced by a
square one and finally on the largest and heaviest version, a rectangular
one. The Ross Bar-limb design became the standard for many British microscope
makers throughout the second half of the 19th century. Some
conservative companies such as Powell and Lealand continued the manufacture
of bar-limb microscopes into the 20th century, long after the
improved continental design. Andrew Ross died in 1859 and his son Thomas Ross
carried on the business. Thomas Ross died about 1870. The Ross company went
on to produce optical products well into the twentieth century, although
large high-quality microscopes became less important as the years went by.
The firm was called Ross & Co between 1837 and 1841, and Ross Limited
from 1897. The firm discontinued the production of microscopes in 1906.
Microscope 153 is signed ‘Ross, London’ and has the serial number 8554, being
dated to c. 1905. It is as example of the Ross’ Improved No. 2 ‘Standard’
microscope (Figure 1, left), displaying the square horseshoe base typical of
late 19th century design found in German microscopes. The
instrument was supplied with a unique substage fitting (Figure 1, centre),
the condenser being hinged to the mounting of the upper dome-shaped iris
diaphragm, so that it can be instantly swung downwards, leaving this iris in
situ, the distance of this diaphragm from the stage being readily varied by
the substage screw. The condenser can be immediately reinserted by a single
movement without disturbing the position of the instrument, and thus altering
the lighting. The mechanical stage can be easily attached or removed and is
so constructed that it will register to the exact position it previously
occupied, in order that an object can be readily found by means of
the vernier (Figure 1, right). This instrument was one of the last
microscopes produced by the Ross company, as the firm discontinued the
production of microscopes in 1906.
Figure
1. Ross’ Improved No. 2 ‘Standard’ microscope (left),
swinging substage fitting (centre) and mechanical stage (left), as engraved
in the 1904 volume of the Journal of the Royal Microscopical Society. Reference Moody Medical Library
(https://www.utmb.edu/ar/moody-medical-library/blocker/artifacts/microscope-collection/british), last accessed on
28.11.2020 LAST
EDITED: 28.11.2020 |
