Beschreibung:

A fine George II cased set of mathematical drawing instruments Thomas Heath, London, circa 1740 The lower tier comprising: A large mathematical sector rule signed and engraved No. 43 annotated with the usual logarithmic, trigonometric and other scales; an oblong protractor rule signed and engraved with trigonometric scales to verso; an expanding parallel ruler with hinged perpendicular distance scales at each end; a set of gunner's callipers, one side with table annotated with tables of the specific weights of named metals and other substances opposing scale giving ordnance bore sizes, the axis with protractor scale and the outer straight edge calibrated in metric inches, the reverse with table for IRON GUNS, Proof, Service tabulated for 1-42 pounder cannon to upper limb and conforming table for BRASS GUNS to lower limb, the axis with scale for shot size, the pointers with iron blade inserts, signed; a large brass proportional dividing compass with sharp steel tipped arms each pierced with long slots for the sliding pivot assembly with knurled screw for securing against scales divided for Circles and Lines, signed; a compass beam calibrated for barometric inches and with fine screw adjustment to one end; together with a large hinged compass with series of interchangeable attachments for the legs and small quantity of other items. The upper tier comprising: An ivory sector rule engraved with trigonometric tables and calibrated for various European inch measurements; a group of five small ivory rules each divided for differing Poles and Parts; a circular protractor with single crossing; an adjustable folding rhombus incorporating vernier protractor scale for setting the smaller internal angles, signed; a double ended compass, together with a set of dividers, an assortment of various tips and other accessories. All contained in a green-velvet lined fishskin covered box with decorative external brass clasp to exterior, the box 41cm (16ins) wide. Thomas Heath is recorded in Clifton, Gloria Directory of British Scientific Instrument Makers 1550-1851 as apprenticed to Benjamin Scott in 1712. Heath presumably gained his freedom of the Grocer's Company before 1720 when he is recorded as working from 'Hercules & Globe next the Fountain Tavern' in the Strand, London. Latterly (from 1734-46) he also worked from an address with the same name near Beaufort Buildings as well as a third premises near Exeter Buildings (1750). He was known to have sold compasses, an astronomical clock, gunner's callipers, theodolites, sundials, sectors, barometers and drawing instruments and took many apprentices including George Adams (I) in 1726/7. In 1751 Thomas Heath went into partnership with former apprentice, Tycho Wing, with the latter acquiring the business outright in 1753 (which he continued until his death in 1773). Condition report disclaimer