Pocket Microscope by John Clark; No. 49

This instrument by John Clark of Edinburgh (c1725–c1790) is a simple microscope made from silver plated brass mounted on a wooden box. The microscope has a triangular base riveted to the top of the box, and a single rectangular pillar to support the objectives, specimen stage, and mirror (not original) The pillar is hinged in the middle. The microscope optics consists of five biconvex lenses mounted in a slider that is inserted in a dovetailed carriage under a blackened eyecup. They are numbered 1–5, with "1" having the highest magnification. There are four sample slides with this instrument. The slides are made of two silvered metal plates, with the sample mounted between the plates and two mica sheets. The slide mounts into a dovetail carriage, much like the objective slider, and is attached to the focus mechanism. Specimens range from cloth to the typical flea.

This microscope has a screw thread focus mechanism that moves the stage mounting block up or down. The focus knob descends from the upper support. At the base of the microscope is a single sided plane mirror. The box is probably not original, but rather a 19th Century case made for a Gould-type instrument. On the back of the upper support is engraved in script John Clark Inv. Fec. Edinb. The microscope is 9.5cm tall.

John Clark was an optical instrument maker, jeweller, and goldsmith whose shops were located in Edinburgh Scotland between 1749 and 1796. He was the second earliest Scottish microscope maker (John Finlayson was the first in 1743) and produced high-quality instruments that optically were much better than compound microscopes at the time. Clark first offered microscopes, made in silver, for sale in 1749, subsequently modifying their design in 1754, and ultimately advertising a brass instrument in 1773. John Clark had at least three shops: one at James Gilliland's Jeweller, at the upper-end of the Luckenbooths (1749); one at Parliament Close (1751-55); and one at Sir Isaac Newton's Head, a little above the Guard, north side of the High Street (1773-82). The microscope shown here was made at his location on High Street in Edinburgh.

The microscope is a modification of Clark's "New Silver Microscope" of 1754; an example of which is in the Royal Scottish Museum. The fact that this microscope is silver plated made it more expensive to buy and therefore more rare than his other brass examples.

This instrument is an example of John Clark’s first foray into microscope design, first made and sold on subscription in 1749, and again advertised for sale in 1751. It is a precursor to his second silver microscope – also first made under a  subscription process in 1754 – and the brass instrument again initially sold on a subscription basis in 1773.  It is the sole surviving example known (D.J.Bryden BSc MA PhD FSA*).

*‘Three Edinburgh Microscope Makers: John Finlayson, William Robertson and John Clerk’, Book of the Old Edinburgh Club, 33 (1972), 165-76. –see plate 6, fig a

Featured 03/2013, 12/2019

Age: c1770
Made by: John Clark
Made in: Edinburgh, Scotland
John Clark Inv. Fec. Edinb.
Specimen samples