. Appleton's dictionary of machines, mechanics, engine-work, and engineering. :B££:v.\\ - V;.s-\^-Vv\\»\»« -II p^vy-0:- distance, and project over them fine iron filings as before; similar results ensue. Magnetic lines offorce, both straight and curved, and proceeding from similar points of each bar, will be apparent, unitingthe two poles by chains of reciprocal attraction. Change the position of one of the bars, so as to oppose two similar poles N N, Fig. 2682; the lines offorce will then appear to be conflicting lines ; the repulsive forces will cause a straight line a 6 to appearon
. Appleton's dictionary of machines, mechanics, engine-work, and engineering. :B££:v.\\ - V;.s-\^-Vv\\»\»« -II p^vy-0:- distance, and project over them fine iron filings as before; similar results ensue. Magnetic lines offorce, both straight and curved, and proceeding from similar points of each bar, will be apparent, unitingthe two poles by chains of reciprocal attraction. Change the position of one of the bars, so as to oppose two similar poles N N, Fig. 2682; the lines offorce will then appear to be conflicting lines ; the repulsive forces will cause a straight line a 6 to appearon the open space or field between the poles, from which the iron dust stands out transversely. Atthis line, the opposed forces on either side are apparently struggling with each other, being exerted inrepulsive directions from the opposed poles. B 2683. C J\ ? i 2084. We have in these phenomena satisfactory visual evidence of the existence of two distinct forces—oftheir reciprocal attractions and repulsions, and their mutual neutralization. A light magnetic bar NS, Fig. 2683, or a small magnetic steel cylinder, of great comparative length,has been termed a magnetic needle. When delicately poised on a central point c, so as to retain a hori-zontal position, and move freely in a horizontal plane, it has been termed the horizontal needle. Whenpoised on a fine central axis, so as to move freely in a vertical plane, it has been termed a vertical ordipping needle. If suspended as in Fig. 2683, so as to have motion in both a horizontal and verticalplane, it has been termed the horizontal and vertical needle. Instruments for ascertaining whether a substance has polarity or not, and for detecting the presenceand kind of force in operation, have been termed magnetoscopes. The most simple kind of magneto-scope is a small horizontal
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Keywords: ., bookcentury1800, booksubjectmechanicalengineering, bookyear1861
