Distillation, Electric. The distilling of a liquid by the employment of electricity, which, by electrifying the liquid, assists the effects of heat. It is asserted that the process is accelerated by the electrification of the liquid or fluid, but it must be a conductor liquid or electrolyte. Oil, being a non-conductor, is not affected by any electric current, no matter what its specific gravity may be.
Distributing Centre. The centre of distribution in a system having branch circuits, such as the electric-light or telephone outlets from a main station.
Door-opener, Electric. A magnetic contrivance arranged in connection with a lock, by means of which the latch is released by pressing a distant push-button. This device is used in flats and apartment-houses for opening a door from any of the apartments in the house.
Double Filament Lamp. An incandescent lamp having two filaments, one with a high capacity, the other with a low one. The high capacity may be from sixteen to fifty candle-power, the other from one to five. A turn of the bulb in its socket, or the pulling of a string which operates a switch in the socket, cuts out the current from the long filament and sends it through the shorter and finer one, thus giving a weaker light. These “hy-lo” lamps are useful as night lamps in halls, bath-rooms, or in sick-rooms, where a low or weak light is required all night.
Double Pole-switch. A cut-out that is arranged to cut out the circuit of both the negative and positive leads at the same time.
Double-push. A contact-push having two contacts and arranged so that pressure upon it opens one contact and closes the other.
Double Throw-switch. A switch so arranged that it can be thrown into either one of two contacts; a throw-over switch.
Driving-pulley. The broad-faced or channelled pulley on an armature shaft by means of which the power from a motor may be transmitted mechanically.
Dry Battery. (See [Battery, Dry].)
Duct. The space in an underground conduit for a single wire or cable.