A telephone transmitter and a receiver on a novel plan were patented in July 1877 by Edison, shortly after the introduction of Bell's instruments.
Sherard Cowper Coles patented a process in which, working with a high current density, a lead anode is used, and powdered zinc is kept suspended in the solution to maintain the proportion of zinc in the electrolyte, and so to guard against the gradual acidification of the bath.
The only modification of water-retting which has hitherto endured the test of prolonged experiment, and taken a firm position as a distinct improvement, is the warm-water retting patented in England in 1846 by an American, Robert B.
Four years later Varley patented his artificial cable, which was the first near approach to a successful solution of the duplex problem on the principle now adopted.
Hence processes have been patented in which the objects to be plated are suspended in revolving drums between the anodes, the rotation of the drum causing the constant renewal of surfaces and affording a burnishing action at the same time.
The spinning jenny, which was patented by James Hargreaves (d.
Many modifications have been patented by Hermite, that of 1895 specifying the use of platinum gauze anodes, held in ebonite or other frames.
The torque T at any instant of steady running is therefore I WR Lord Kelvin patented a brake in 1858 (fig.
In 1886, however, Castner replaced the carbonate by caustic soda, and materially cheapened the cost of production; but this method was discarded for an electrolytic one, patented by Castner in 1890.
The use of reflecting mirrors for the purpose of observing from cover is no novelty, and during the trench warfare of the Crimean War 1854-5 a device was patented which scarcely differs from the simple mirror periscope of the World War.