拍品專文
The Troughton & Simms catalogue of circa 1830 lists two repeating circles, one 12-inch priced at (84 and an 18-inch priced at (105.
細節
TROUGHTON, London
A brass repeating/reflecting circle, signed on the circle Troughton, London, the circle divided 0°-360° with subdivisions, silvered scale, the circle frame with eight tapering triangular spokes, the slender outer-frame with four silvered vernier scales, two articulated magnifier arms, the axis with 1¾in.(4.5cm.) telescope with rack-and-pinion focusing,the 18in.(57cm.)diam. circle with two slide locks on the inner rim, the axis secured to the double quadrant scale with bubble level, the scale divided with two ivory scales, the 26in.(66cm.)long telescope mounted below the axis, with rack-and-pinion focusing with counter-balance weight, vertical supports on two vertical supports on tapering pillar, the horizontal circle at the back with silvered-scale, three verniers with single magnifier, on tripod stand with three adjustable screw feet, in fitted pine carrying case, some old damages, some minor parts lacking, circa 1810
See colour plate
A brass repeating/reflecting circle, signed on the circle Troughton, London, the circle divided 0°-360° with subdivisions, silvered scale, the circle frame with eight tapering triangular spokes, the slender outer-frame with four silvered vernier scales, two articulated magnifier arms, the axis with 1¾in.(4.5cm.) telescope with rack-and-pinion focusing,the 18in.(57cm.)diam. circle with two slide locks on the inner rim, the axis secured to the double quadrant scale with bubble level, the scale divided with two ivory scales, the 26in.(66cm.)long telescope mounted below the axis, with rack-and-pinion focusing with counter-balance weight, vertical supports on two vertical supports on tapering pillar, the horizontal circle at the back with silvered-scale, three verniers with single magnifier, on tripod stand with three adjustable screw feet, in fitted pine carrying case, some old damages, some minor parts lacking, circa 1810
See colour plate
出版
Bennett, J.A., The Divided Circle, a similar example is illustrated on the front cover.