Sinossi
This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1908 Excerpt: ...C, fig. 97), according as I change the direction of the current. It gives one the impression of the tinfoil strip being attracted, first by the R and then by the L half of the frame. A glance at the indicator of the commutator shows that the movable conductor is attracted to that side of the frame where the current has the same direction as itself. Now I modify the experiment by placing the wire frame quite close to the tinfoil strip and close the circuit. When the current is in the same direction there is attraction, but when it is opposite Fig. 97.--Action of a fixed current conductor on a movable one, natural size. there is a distinct repulsion (D, fig. 97). We therefore derive the following rule: Electric currents flowing in the same direction attract each other, those flowing in opposite directions repel one another. If our observation is right, then a current conductor, free to move, will strive to place itself in the same direction and parallel with another which is placed near it; therefore, under certain condi I L Fig. 98.--Modified and simplified Ampere's parallelogram, fa natural size. B. Contact cup, 4 natural size. (The platinum should just dip in.) R should consist of ten turns. tions, it displays a directing force. We will now put this to the test. An open wire frame, the "solenoid" (R, fig. 98 A), consisting of ten turns of covered copper wire 0-5 mm. thick, is suspended from a fine hair (or from an unspun silk thread), in such a way that the ends, to which platinum points of 40 mm. length are soldered, just dip respectively into two small cups of mercury, 1 It is recommended to flatten the end of the wire dipping into the outer cup, Bo that it may turn more easily in the mercury. The wires must dip in very slightly, and the mercur...
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