Miner's Safety Electric Lamp, 1886

Electric lamp, 1886. This lamp, patented by Sir J W Swan, was the forerunner of modern electric lamps. The box contains four secondary cells in series.

In this form, patented in 1886 by Sir J. W. Swan, a glow lamp with a reflector behind, protected by a bullseye lens, is attached to the front of a cylindrical teak box accommodating a battery of four secondary cells in series. These are made liquid tight by a cover tightly screwed down, so that the lamp may be inclined. The switch is in front, and contact plates for charging are on the bottom. The light given is about 2 c.p., diminishing to less than 1 candlepower in 10 to 12 hours. A charging current of 0.5 amps. at 10 volts for about the same period is required.