. Supplement to Spons dictionary of engineering, civil, mechanical, military, and naval. is of Grays receiving telephone; in using this instrument the thin metal chamber isconnected through the stand to one terminal of an induction coil, in circuit with the musical soundtransmitted at the distant station, and the operator, taking hold of a wire a connected to the otherterminal, presses his fingers on the metal surface while he turns the handle with the other this simple apparatus every tune played at the transmitting end is reproduced, and the more rapidthe rotation the louder the so
. Supplement to Spons dictionary of engineering, civil, mechanical, military, and naval. is of Grays receiving telephone; in using this instrument the thin metal chamber isconnected through the stand to one terminal of an induction coil, in circuit with the musical soundtransmitted at the distant station, and the operator, taking hold of a wire a connected to the otherterminal, presses his fingers on the metal surface while he turns the handle with the other this simple apparatus every tune played at the transmitting end is reproduced, and the more rapidthe rotation the louder the sound, no sound whatever being emitted when the rotation is suspended. Graham Bells articulating telephone was introduced in 1876, and is largely in use. In its earlystage the transmitting instrument consisted of a horizontal electro-magnet, in front of which andperpendicular to the plane of its axis is fixed a brass ring; over this a membrane is stretched,tightened by means of screws ; to the centre of this membrane is attached a small oblong piece of ELECTEICAL ENGINEEEING. 583 iron, situated immediately in front of, and almost in contact with, the poles of the electro-magnet ;binding screws on the stand of the instrument are used to place the coils in circuit with the receivinginstrument. This was formed of a thick tube of soft iron, enclosing a vertical bar electro-magnet,rather shorter in length than itself, the two being so connected at the lower end that, while thecentral bar under the influence of the current assumednorth magnetic polarity, the tube surrounding it becameby induction a south pole of annular form. To the topof this tube was fastened, by a small screw, an iron discabout the thickness of cartridge paper, and this disc,under the influence of a voltaic current, was held firmlydown by the annular pole, its centre being in frontof the shorter central pole. It thus constitutes a dia-phragm held by its edge by magnetic attraction, itscentre being presented t
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Keywords: ., bookcentury1800, bookdecade1870, booksubjectenginee, bookyear1879
