Farrow's military encyclopedia : a dictionary of military knowledge . the jirimary and secondary wiresside by side round a bolibin, so as to forma coil. The wires are insulated from each other by a cover-ing of wool or silk. Not only does such a disposi- I tion admit of very long wires being used, but it alsodisposes the wires emi)l(jyed to greater advantage, j for each single turn of the primary wire acts notonly on the corres])onding turn of the secondary wirebut on all the turns near it. The inductive effect of \ such a coil is much greater than that which would i be obtained tiy the same e
Farrow's military encyclopedia : a dictionary of military knowledge . the jirimary and secondary wiresside by side round a bolibin, so as to forma coil. The wires are insulated from each other by a cover-ing of wool or silk. Not only does such a disposi- I tion admit of very long wires being used, but it alsodisposes the wires emi)l(jyed to greater advantage, j for each single turn of the primary wire acts notonly on the corres])onding turn of the secondary wirebut on all the turns near it. The inductive effect of \ such a coil is much greater than that which would i be obtained tiy the same extent of wires running sideby side in a straight or crooked line. It is not evennecessary that the two wires be wo\md round toireth-er, each may be wound (m a separate bobbin, andthe one placed inside the other. The primary coil ismade of wire one-twelfth of an inch in diameter,covered with wool: and the secondary coil of silk-covered wire,one-eighteenth of an inch! much longerthan the primary wire. With two such coils, many I principles of induction can be now, when the needle is at rest, the battery circuitbe broken, and the current stopped, another momen-tary current is indicated by the galvanometer needlebut in this case in the .same direction as the inducingcurrent. The inducing wire and current are calledprimary, and so are distinguished from the inducedvpire and current, which are termed secondary. Thepassive condition of the wire while thus under in-duction has been described by Faraday as electro-tonic. An electric throb, so to speak, makes thesetting in of this state, and another its vanishing ;the former in the opposite direction to that of the in-ducing current, and the latter in the same the primary wire be movable, so that it can besuddenly brought near to, and withdrawn from thesecondary, while the battery current passes steadily,currents are induced as in the former case, the ap-proach of the wire being marked by an inverse cur-rent, and its
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Keywords: ., bookcentury1800, bookdecade188, booksubjectmilitaryartandscience
