Microscope Museum

Collection of antique microscopes and other scientific instruments

Microscope 535 (J Casartelli & Son; cloth counting glass; c. 1970)

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. After his father’s death in 1900, Joseph Henry carried on the business followed by his sons. In 1905, the works were moved to Hayes Yard, Garret Street, Manchester. Casartelli’s business moved to 18 Brown Street, Manchester, in 1922, and later acquired the business of another family member in Liverpool in 1929, which had been in the hands of Anthony Casartelli and Sons. However, the Liverpool branch was liquidated during the Great Depression in 1933. Part of the business continued under different ownerships until 1966, making surveying and textile instruments. In 1966, the firm moved to Liverpool Street, Salford, but soon after that they made the decision that there was no longer the demand for manufacturing surveying and textile instruments. Eventually, in 1989, the Casartelli firm ceased trading. Microscope 535 is a microscope cloth counting glass, engraved with ‘J. CASARTELLI & SON’, ‘SALFORD 6’, and ‘R^D 14755’. The instrument should be dated from c. 1970 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). This instrument contains a scale along which a pointer moves so that the number of threads per unit of length can be counted. The lens is suspended above the pointer, which moves via a screw. Figure 1 shows this instrument as featured in an undated J. Casartelli & Son’s brochure.

Note: microscope 535 was kindly donated by Mr Frank van Wijk (Zeist, The Netherlands) in December 2024, in the name of the late T.R. Hartendorp, a collector of objects related with physics among other fascinating items.

Figure 1. Microscope cloth counting glass, Reg. No. 14755, as featured in an undated J. Casartelli & Son’s brochure.