FIRING DYNAMITE BY ELECTRICITY

Te Aroha News, Volume XIV, Issue 2069, 18 January 1898, Page 2

FIRING DYNAMITE BY ELECTRICITY

At the Verbelia (Colorado) tunnel the dynamo used is located in' the gulch 25ft. from the mouth of the tunnel; wires are run into the tunnel connecting with the electric caps, which, when the current is turned on, explodes the dynamite. This electric cap, in construction, resembles an incandescent lamp, inasmuch as it has two wires leading into it with a filament of platinum, but it differs from the incandescent lamp filament in action ; the filament in the lamp is Strong enough to carry the current whioh makes a it incandescent, and therefore gives out a steady light, but the filament in the cap is not strong enough to carry the but burns off, causing an electric spark to ignite the fulminating powder in the bottom of the cap and explode, thus exploding the dynamite. The wire and filament in the cap are held in place by sulphur, which is poured in while it is hot, thus making the 'cap waterproof. The dynamo, which connects by wires with a round of holes in the tunnel, has a a pull up or a push-down handle, which is connected to the armature by means of cog-wheels which cause it to revolve at a high rate of speed, thus generating a large quantity of current, which is held in the dynamo by means of a short circuit until the armature has gained its highest speed, when the short circuit is automatically broken, allowing the current to flow through the caps and causing them to explode. This is a safe Way of exploding dynamite, because the miner must get out of his shaft or tunnel before the. current can be turned on, and, consequently, there is no danger of any of the shots going off prematurely or of any of them hanging fire ; and*-to,be doubly safe, the miner can keep his dynamo locked and his key in his pocket.