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Microscope Museum Collection of antique microscopes and other
scientific instruments |
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Microscope 458 (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 458 is a cloth counting glass and is engraved with ‘CASARTELLI, MANCHESTER’, and with ‘JOHN M. SUMMER & Co, MANCHESTER’ (but not much information was found about this second firm). The instrument 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. |
