Davis's manual of magnetism : including galvanism, magnetism, electro-magnetism, electro-dynamics, magneto-electricity, and thermo-electricity . h pole of the magnet,as shown by the dotted lines in thecut, the polarity of the lower end im-mediately disappears. This is be-cause the two poles tend to induceopposite polarities of equal intensity inthe extremity of the armature, whichof course neutralize each other. If the branches ofthe fork are applied to the similar poles of two mag-nets, their influence will conspire in inducing thesame polarity in the lower end, and a greater weightwill be su
Davis's manual of magnetism : including galvanism, magnetism, electro-magnetism, electro-dynamics, magneto-electricity, and thermo-electricity . h pole of the magnet,as shown by the dotted lines in thecut, the polarity of the lower end im-mediately disappears. This is be-cause the two poles tend to induceopposite polarities of equal intensity inthe extremity of the armature, whichof course neutralize each other. If the branches ofthe fork are applied to the similar poles of two mag-nets, their influence will conspire in inducing thesame polarity in the lower end, and a greater weightwill be supported by it, than when one branch isapplied to a single pole. 228. When the two extremities of an iron bar arescted upon at once by both poles of a magnet, thereis a double induction, and the effect is greatly in-creased. Thus, let N S (Fig. 91) be a compoundU-magnet, and A an iron armature, of such a lengththat, while one end is applied to the north pole of themagnet, the other extremity may be applied to thesouth. In this case, both poles of the magnet act,each inducing a polarity opposite to its own in that IM DAVISS MANUAL. Fig. Fig. 92. extremity of the armature which is under its influ-ence. The force with which the armature adheresis consequently greatly increased, therebeing a strong attraction between eachpole of the magnet and the correspond-ing extremity of the armature, that is,corresponding in position ; for the polar-ity of the parts in contact will evidentlybe of opposite denominations. If a barof iron is placed between the north polesof two magnets, both extremities be-come south poles, while a north pole isdeveloped at the middle of the bar. 229. Rolling Armature.—Thisapparatus consists of a horseshoemagnet and an iron wire or rod,whose length is. a little greater thanthe breadth of the magnet. Tothe middle of the wire a small fly-wheel is attached. This armatureis placed across the magnet, at somedistance from the poles, and themagnet held in such a p
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Keywords: ., bookcentury1800, bookdecade1850, booksubjectmagnetism, bookyear18
