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Microscope Museum Collection of antique microscopes and other
scientific instruments |
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Microscope 300 (J Casartelli & Son;
cloth counting glass; early 20th century)
Guiseppe
Luigi Casartelli (1823 – 1900) emigrated as a child from Italy to Liverpool,
England, joining a relative’s scientific instrument firm business. He changed
his name to Joseph Louis Casartelli and later moved to Manchester where he
established himself as a manufacturer of optical equipment, trading at 43
Market Street for many years. Around 1850, Casartelli produced microscopes,
telescopes and other optical devices. By the 1870s-80s, Casartelli’s business
focussed on supplying the heavy industries of Manchester, including fittings
for steam engines, mining equipment and optical instruments for the fabric
industry. One of Casartelli’s sons, Joseph Henry, was made a partner of the
company and the business became “J. Casartelli and Son” in 1896. Casartelli’s
business moved to 18 Brown Street, Manchester in 1922, acquired the business
of another family member in Liverpool in 1929, but was liquidated during the
Great Depression in 1933. Parts of the business continued under different
ownerships, including the Liverpool business as ‘J. Casartelli & Son
(Liverpool)’ (later ‘Casartelli Instruments Ltd.’, in 1984, which closed in
1989), and the original business became ‘J. Casartelli & Son Ltd.’ (and
then ‘John Casartelli (M/c) Ltd.’ in 1939). Microscope 300 is a cloth
counting glass engraved with ‘CASARTELLI, MANCHESTER’ and should be dated to
the early 20th century. This instrument combines the advantages of
the folding linen prover with the thread counter and would be used for
counting threads in fabrics (the number of threads per unit of length
provides evidence of a higher quality of cloth). The focus is fixed, with a
single combined scale, calibrated in 1/4-inch increments, followed by 10 mm,
calibrated in single mm. There is a pointer that moves, so that the number of
threads per unit of length can be counted. The lens is suspended above the
pointer. Similar instruments were sold by other firms such as R & J Beck
(Figure 1).
Figure 1. Linen prover as featured in a R & J Beck catalogue from the
1920s – 1930s. |
