This section is from the book "A Treatise On Architecture And Building Construction Vol3: Stair Building, Ornamental Ironwork, Roofing, Sheet-Metal Work, Electric-Light Wiring And Bellwork", by The Colliery Engineer Co.. Also available from Amazon: A Treatise On Architecture And Building Construction.
102. In the application of electricity to gas lighting, a spark is caused to pass between two conductors, placed near the burner, at the same time that the gas is turned on. In the parallel system of lighting, each burner is independent of all the others, having direct connection between the battery wire and ground. Three different styles of burner are used: the pendant, the ratchet, and the automatic burner.
103. The pendant burner is shown in Fig. 82. A well insulated wire is brought to the burner and secured under the head of the screw s, thereby making connection to the stationary contact piece c, which is fastened by a screw l to the frame f, and insulated from it by washers w. On pulling the pendant r downwards, the spring a is drawn across c, and, on passing off at the upper side, the break causes a spark which, when the gas has been turned on, will ignite it.
104. The ratchet burner is very similar to the plain pendant, and is provided with a ratchet and pawl operated by a pendant, a downward pull turning on the gas at the same time that the spark is produced. A second pull extinguishes the gas.
105. The automatic burner is shown in Fig. 83, with the cover removed. Two wires must be provided, running from a double push button, one of them leading to the wire a, and the other to b. The circuit from a is through the left-hand magnet coil c to the insulated band d, which has a projection e at one side. Upon this rests a metal rod r, bent at the upper end, and terminating in a contact piece; at the lower end the rod is grounded by connection with the frame f. Each magnet coil has an armature, g or g/, with a projecting finger on the inner side. When current is sent through the magnet c, the armature g is raised and turns the gas valve v by striking one of the pins. At the same time the rod r is pushed up, thus breaking the circuit at a point where the gas is escaping, and producing a spark which will ignite it. To provide for certain action, the sparking should continue later than the instant of turning on the gas, and this is effected by the use of a spring to restore the circuit. The rod r is forced upwards against the spring s, but, when the circuit is opened at the spark gap, the spring presses the rod and armature down again, and, the circuit being thereby closed, a spark is again produced on opening. This continues as long as the push button is pressed, the action being similar to that of an electric bell. The second coil h is grounded at the inner end, and, when a current is sent through, the armature g' is raised, turning the valve and cutting off the supply of gas.