John Clark (attributed, unmarked), a Scottish brass portable simple microscope, circa 1774, the vertical pillar with folding concave mirrors and various slide bars, screwing into a plate in the velvet-lined holding case, with ivory screw lidded canisters and handwritten slide contents note, the box covered in rayskin, 10.5cm x 6.5cm. Note: Ivory Exemption Certificate No.AY4FY16U

See Bryden, D J, 1972, "Three Edinburgh Microscope Makers: John Finlayson, William Robertson and John Clark", The Book of the Old Edinburgh Club, 33, pt 3, 165-176
and Scottish Scientific Instrument-Makers 1600-1900, Royal Scottish Museum Technology 1 (Dec. 1972b); Christie's, London, 8th April 2004, lot 1 and Lyon and Turnbull, 12th August 2015, lot 110, for identical marked examples by Clark; examples are also held by the Smithsonian Museum

Provenance: from the collections of two prominent Anglo-Irish and British aristocratic families, directly descended from Lord Patrick James Stuart (1794- 1859), brother of John 2nd Marquess of Bute and great grandson of John Stuart, 3rd Earl of Bute (1713 -1792), Prime Minister to George III, resident at Cardiff Castle, Wales; Dumfries House, Scotland and Wilton Crescent, Belgravia, London