Heat. One of the force agents of nature. It is recognized in its effects through expansion, fusion, evaporation, and generation of energy.
Heat, Electric. Caused by a resisting medium, such as carbon or German-silver, when too much current is forced through it. The principle of the car-warmers, electric iron, electric chafing-dish, etc.
Helix. A coil of wire. Properly a coil of wire so wound as to follow the outlines of a screw without overlaying itself.
Horse-power, Electric. Meaning the same as in mechanics. Referred to when speaking of the working capacity of a motor or the power required to drive a dynamo.
Horse-power Hour. A unit or standard of electrical work theoretically equal to that accomplished by one horse during one hour.
Horseshoe Magnet. (See [Magnet, Horseshoe].)
H-P. Abbreviation for horse-power.
Hydrometer. An instrument employed to determine the amount of moisture in the atmosphere.
An instrument for determining through flotation the density or specific gravity of liquids and fluids. It consists of a weighted glass bulb or hollow metallic cylinder with a long stem on which the Baumé scale is marked. Dropping it into a liquid it floats in a vertical position, and sinks to a level consistent with the gravity of the fluid.
Hydrometer, Baumé. An apparatus for testing the gravity of fluids. The zero point corresponds to the specific gravity of water for liquids heavier than water. A gauge, valuable in testing acids and other fluids used in electrical work.