Lot Essay
William Parnell worked between 1811-1839 from three addresses in London; D. McGregor retailed instruments between 1836-1844, when he started producing his own.
Details
An early 19th-Century vernier octant signed Parnell, London
constructed in ebony, ivory and brass, the scale divided 5°- 0°- 102°. the vernier with clamp and fine screw asjustment, six shades, two mirrors, double pin hole sight, ivory note square to back and brass feet, contained within a fitted keystone case with period trade label for D.McGregor & Co. in lid, the index -- 10in. (25.5cm.)
See illustration
constructed in ebony, ivory and brass, the scale divided 5°- 0°- 102°. the vernier with clamp and fine screw asjustment, six shades, two mirrors, double pin hole sight, ivory note square to back and brass feet, contained within a fitted keystone case with period trade label for D.McGregor & Co. in lid, the index -- 10in. (25.5cm.)
See illustration
Literature
Clifton, G: Directory of British Scientific Instrument Makers 1550-1851, Zwemmer 1995