under the supervision of Hooke.
Graham, who attained great reputation as an instrument-maker as well as clock-maker, adopted the principle of continuous bisections by means of a beamcompass.
In the instruments constructed by him for Halley and Bradley, the are of 60° was divided into 64 parts, making 96° instead of 90° to the quadrant.
It was deemed preferable to make the proportionate correction on each angle, rather than to trust to the uncertainty of a division to thirds or fifths.
Bird, 1750, subsequently improved the system by constructing scales of equal parts, enabling him to preserve the division of 90° by successive bisections.
His manual skill and care procured him merited reputation as a maker of accurate instruments.
Ramsden followed with his dividing-engine, 1766, the general principles of which, variously modified and improved by Troughton and others, are still employed in the construction of like instruments.
In this, a horizontal wheel, turning on a verti
, Dec. 3, 1850.
10,586.Meyer, Feb. 28, 1854.
56,670.Cutler, July 24, 1866.
37,523.Roberts, Jan. 27, 1863.
24,695.Eaton, July 5, 1859.
125,707.Walker et al., Ap. 16, 1872.
26,172.Eaton, Nov. 22, 1859.
153,447.Meyer, July 28, 1874.
153,448.Meyer, July 28, 1874.
153,449.Meyer, July 28, 1874.
153,450.Meyer, July 28, 1874.
99,956.Schlesinger, Feb. 15, 1870.99,885.Halliday, Feb. 15, 1870.
Vulcanite Articles. See patents:—
No.Name and DatePurpose.
103,416.Bird et al., May 24, 1870Wringer-rolls, etc.
62,106.Albright, February 12, 1867Harness-trimmings.
77,952.Beins, May 19, 1868Car-springs.
140,519.Mayall, July 1, 1873Belting.
Restoring Waste Rubber. See patents:—
No.Name and Date.
15,998.Forstrick, Oct. 28, 1856.
122,289.Smyser, Dec. 26, 1871.
23,740.Bachnagel, Ap. 19, 1859.
25,160.Hall, August 16, 1859.
30,181.Parmalee, Sep. 25, 1860.
92,764.Tuttle, July 20, 1869.
17,295.Popenhausen et al., May 12, 1857.