. Chamber's scientific reader : illustrated with wood engravings. Readers. 32 PHYSICS. wire to an iron stand. A conductor cut off from communication with the ground by being fixed on non-conductors, in this way, is said to be insulated: Let us now return to our first experiment. "We saw by it that positive electricity attracted negative, and negative, positive ; and also that both attracted bodies not electrified at all: it will now be shewn that the last part of this statement is the same as the first. If a brass cylinder be fixed on a glass stand, with a pair of pith-balls suspended by
. Chamber's scientific reader : illustrated with wood engravings. Readers. 32 PHYSICS. wire to an iron stand. A conductor cut off from communication with the ground by being fixed on non-conductors, in this way, is said to be insulated: Let us now return to our first experiment. "We saw by it that positive electricity attracted negative, and negative, positive ; and also that both attracted bodies not electrified at all: it will now be shewn that the last part of this statement is the same as the first. If a brass cylinder be fixed on a glass stand, with a pair of pith-balls suspended by a cotton thread (not silk this time, because it is not desired to insulate them from the cylinder) at either end, and placed near another insulated conductor •charged with positive electricity, this is what will happen—the balls will be repelled from each other, as in the figure, shewing that each pair has become charged with the same kind of electricity. But it is found that the electricity at the two ends is of different kinds, that in the end next the ball being nega- tive, while that in the other end is positive. This is quite in accordance with the result of our first experiment, that positive electricity attracts negative, and repels positive, and vice versd. From this it is< manifest, that in all conductors there exist (with- out friction) the two kinds of electricity, and that these are acted upon by an electrified conductor exactly in the same way as if the electricity had been produced by friction in both. It will now be seen that, when the rubbed glass attracts the pith-ball the first time, the attraction is not different from the subsequent attractions ; the positive electri- city in the glass repels the positive in the ball to the opposite side, and attracts the negative. This attraction is great enough to overcome the slight weight of the ball; when contact takes place, the negative electricity in the side of the ball next the glass is replaced by positive
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Keywords: ., bookcentury1800, bookdecade1870, bookpublisherlondo, bookyear1872
