This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1889 Excerpt: ... substance of high resistance, through which the current is passed. These coils or circuits are surrounded by air or finely divided solids, and placed inside metallic boxes, or radiators, which throw off or radiate the heat produced. When employed for the heating of liquids the coils are placed directly in the liquid ...
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This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1889 Excerpt: ... substance of high resistance, through which the current is passed. These coils or circuits are surrounded by air or finely divided solids, and placed inside metallic boxes, or radiators, which throw off or radiate the heat produced. When employed for the heating of liquids the coils are placed directly in the liquid to be heated, or are surrounded by radiating boxes that are placed in the liquid. Heating Effect of Current.--(See Heat, Electric. Calorimeter, Electric. Joule's Laws.) Hecto (as a preflx.)--One hundred times. IIcliccM, SiniHtrorgal and Dcxtrorsal----Coils of wire so wrapped or wound that when traversed by an electric current they acquire all the properties of magnets. (See Solenoids, Sinistrorsal and Dextrorsal.) Heliograph.--An instrument for telegraphic communication by means of flashes of light, which represent the dots and dashes of the Morse alphabet, or the movements of the needle of the needle telegraph to the right or left. (See Alphabet Telegraphic.) The flashes of light are thrown from the surface of a plane mirror. Motions to the right or left may be used to distinguish between the dots and dashes, or the same purpose may be effected by the relative durations of the flashes of light, or by the intervals between successive flashes. Similar telegraphic communication has been carried on between steamers during foggy weather by means of their fog horns, or between locomotives, by their steam whistles. Hermetlcal Seal.--Such a sealing of a vessel, designed to hold a vacuum, or gaseous atmosphere under pressures greater or less than that of the atmosphere, as will prevent either the entrance of the external atmosphere into the vessel, or the escape of the contained gas into the atmosphere. Hermetical sealing may be accomplished either by ...
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