Oldham miner's electric safety lamp cap type, with magnetic lock, accumulator, cap and belt

This electric lamp, designed for wearing on the head, has been approved for use in this country. The accumulator is of the rectangular type and is carried in a metal case strapped round the waist of the miner. The case, which weighs about 5 lb., is most conveniently carried on the back or over the hip. The electrolyte used in the accumulator may be either solid or liquid, but the design of the accumulator obviates risk of spilling acid even when liquid electrolyte is used. The accumulator case is locked magnetically in the example shown, but lead plugs are also fitted. A rotary screw down switch is also mounted on the cell case by means of which the light may be controlled. The light bulb itself is carried in the front of a canvas cap and is connected to the cell by means of a very flexible, highly insulated, rubber -encased cable which is armoured at both ends, where the greatest bending stress is experienced, by steel springs wound round the outside. The lamp is rated to give an illumination of 3 candlepower for 10 hours continuous service with a considerable safety margin for exceptional circumstances. The glass in front of the light bulb is quite plain to give a diffuse illumination, but when a concentrated light is required the plateglass front of the lamp can be replaced by a suitable lens.