““A coil of platinum wire is attached to two copper wires, the lower parts of which, or those most distant from the platinum, are well varnished; these are fixed erect in a glass of distilled water, and another cylindrical glass, closed at the upper end, is inverted over them, so that its open mouth rests on the bottom of the former glass; the projecting ends of the copper wires are connected with a voltaic battery (two or three pairs of the nitric acid combination), and the ignited wire now gives a steady light. Instead of making the wires pass through the water, they may be fixed to metallic caps well luted to the necks of a glass globe.””
In 1845 August King patented, in England, an incandescent lamp, having an unsealed platinum burner, and also a carbon in a vacuum. Mr. King acted as agent for an American inventor, Mr. Starr, and the lamp came to be known as the Starr-King lamp, shown in [Fig. 50]. The burner was a thin plate or pencil of carbon B, enclosed in a Torricellian vacuum at the end of an inverted barometer tube, and held between the terminals of the connecting wires leading to a battery. In 1859 Moses G. Farmer lighted his house at Salem, Mass., by a series of subdivided electric lights, which was the first private dwelling lighted by electricity, and probably the first illustration of the feasibility of subdividing the electric current through a number of electric lamps.
In 1877 William E. Sawyer applied for a United States patent for an electric engineering and lighting system, and in January, 1878, entered into a partnership with Albon Man, and the “Sawyer-Man” lamp, see [Fig. 51], was produced. In this an incandescent rod of carbon was inclosed in an atmosphere of nitrogen. This marked the beginning of a period of great activity in this field, which finally resulted in the well known form of electric lamp shown in [Fig. 52], which was patented by Edison, No. 223,898, January 27, 1880. The distinctive features of this lamp consisted in a bowed filament of carbon of very thin, thread-like character, which was made of paper or carbonized cellulose. This, when sealed in a vacuum, would not burn away, but would give the proper incandescence, and by its small transverse dimension and high resistance to the current, permitted a proper distribution of the electric current to a number of lamps, without a special regulator for each lamp; and which could also be made so cheaply that the lamp could be thrown away when the burner was finally broken. Edison’s claim on this feature of the electric lamp was sharply contested in an interference in the Patent Office by Sawyer and Man, with the decisions alternating first in favor of one and then of the other, but which finally resulted in the grant of a patent to Sawyer and Man, on May 12, 1885. A struggle then began in the courts, which on October 4, 1892, terminated in a decision by the United States Court of Appeals (Edison Electric Light Company vs. United States Lighting Company), awarding the incandescent lamp to Edison.
FIG. 51.—
SAWYER-MAN
LAMP.
FIG. 52.—EDISON’S ELECTRIC LAMP.
A—Exhausted globe. B—Carbon filament. CC—Wires sealed in glass. D—Line of fusion of two parts of globe. EF—Insulating material. G—Screw-threads. HI—Metal socket. J—Fixture arm K—Circuit controlling key.