A rare 18th-Century Scottish simple microscope,

No VAT will be charged on the hammer price, but VA… Read more

MICROSCOPY

Details

A rare 18th-Century Scottish simple microscope,
signed and dated Jn Clark EDINR 1775, in a rayskin-covered wooden case -- 10.5 x 6.7 x 3.8cm. (4 1/8 x 2 5/8 x 1½in.)

See Illustrations

The small fitted box forms the supporting stand when the lid is fully opened. A wooden block in the centre of the base holds a brass rectangle which has a threaded hole at the middle, surrounded by the signature and date. A brass ogee-shaped support screws into the hole, to which is hinged at the bottom a concave mirror and at the top a dove-tailed bracket to hold the operative part of the microscope. This is formed from a brass rectangular plate with dovetail slides on both sides, one to hold the stage with a long fine-focus screw; the other, moved manually, holds the objective wheel. This carries 5 simple objective lenses (1 through 5), each with its number viewed through an aperture as the wheel is rotated by means of its knurled edge. Next to the wheel at the side nearest the viewer, is a rectangular aperture in which swivels a plate with a plane mirror for top illumination of an opaque specimen when used in conjunction with the substage mirror. Clark considered this better than a lieberkuhn.
The stage frame projects horizontally from the stand with a dovetailed carriage in which slides a brass transporter (3½in. long) with 9 small apertures (diameter 0.2in.), only two of which now hold specimens between mica slips (bee's knee joint and wing). A second carriage (3 1/8in. long) has three rectangular apertures, one with a hinged matching aperture to hold down a specimen. A third holder (3½in. long) has three apertures, one with stage forceps and a spike. Two ivory screw-top boxes are for mica slips (known as talcs) and brass split rings; one ring remains, but no talcs.
The domed box is made of wood covered on the outside in black rayskin , and on the inside in olive-green silk.

Literature

BRYDEN, D.J., "Three Edinburgh Microscope Makers: John Finlayson, William Robertson and John Clark", The Book of the Old Edinburgh Club, 33, pt 3 (1972a) 165-176
--, Scottish Scientific Instrument-Makers 1600-1900, Royal Scottish Museum Technology 1 (Dec. 1972b)

Special notice

No VAT will be charged on the hammer price, but VAT at 17.5% will be added to the buyer's premium which is invoiced on a VAT inclusive basis

Lot Essay

John Clark (working 1749-1796) was an Edinburgh goldsmith, jeweller and optical instrument maker. He first made his 'new improved pocket microscope' in 1773, basing it on an earlier design of 1754; both were priced at 4 guineas. Only five of these 'new' microscopes were known to Bryden (1972a).

More from EXCEPTIONAL SCIENTIFIC AND ENGINEERING WORKS OF ART

View All