The London, Edinburgh and Dublin philosophical magazine and journal of science . able I. Position ofrest. Negativethrow. Positivethrow. Calculatedpositivethrow. 5 1 45 46 10 2 9 91 15 3 13 132 20 4-5 17 171 25 5 20 20-3 30 6 22-5 23 35 7 24-5 25 40 7-8 26-2 26 2 45 8-8 26-5 26-5 50 8-5 26-2 26-2 55 8-2 24-5 25 60 7-8 22 23 65 75 20 20-3 70 6-5 16 17*1 75 5-5 12-5 13-2 80 35 9 9-1 85 2 4 4-6 The close agreement of the other numbers shows clearly Magneto-electric Phenomenon. 221 that, on breaking the circuit, the impulse is truly proportionalto sin 2a. Examination shows that the negative impulse
The London, Edinburgh and Dublin philosophical magazine and journal of science . able I. Position ofrest. Negativethrow. Positivethrow. Calculatedpositivethrow. 5 1 45 46 10 2 9 91 15 3 13 132 20 4-5 17 171 25 5 20 20-3 30 6 22-5 23 35 7 24-5 25 40 7-8 26-2 26 2 45 8-8 26-5 26-5 50 8-5 26-2 26-2 55 8-2 24-5 25 60 7-8 22 23 65 75 20 20-3 70 6-5 16 17*1 75 5-5 12-5 13-2 80 35 9 9-1 85 2 4 4-6 The close agreement of the other numbers shows clearly Magneto-electric Phenomenon. 221 that, on breaking the circuit, the impulse is truly proportionalto sin 2a. Examination shows that the negative impulses,though in reality equal to the others, are apparently much lessin amount, that they are not even in proportion, and not onlythis, but that the corresponding values on either side of 45° arenot the same. This want of symmetry is clearly shown byfig. 1. The discrepancy is due to the fact that the disk isbrought to rest by the damping action of the field as well asby the torsion of the wire, and that the damping action isgreater as the angle is less, being : : cos2 a. Fig. I thought it would be interesting to determine to whatangle the disk would be thrown if the torsion of the wire didnot act. I therefore suspended, instead of the disk, the coilused in the absolute experiments by a silk thread, adjusted thelower card by the method of no throw, and brought the indexto rest successively over 10°, 20°, 30°, &c. up to 90°. Theindex came to rest at the series of positions shown in column 2of the following Table:— Table II. Pointer fell From To 10 36 20 6 30 10 40 13 45 16 50 18 60 22 70 29 80 39 The same results are shown graphically in fig. 2. It is 222 Mr. C. V. Boys on a interesting to note that the curve shown is a natural curvedepending on circular functions only. It is independent ofthe nature of material, such as conductivity, moment of inertia,or of the strength to which the field is made to grow fromzero. It is subject to a small error, for I did not destroy ther
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Keywords: ., bookcentury1800, bookdecade1840, bookidlondon, booksubjectscience
