312 Experiments upon the Induction of Metallic Coils. 
the covering, and which obliquity in the contiguous layers was in an 
opposite direction. As the ribbon was one inch in width and the 
iron one inch in diameter, the angle at which the layers crossed each 
other was more than 45°. 
4. The whole horse shoe was then weet with the same ribbon 
singly, and that which was left after covering it was then coiled spi- 
rally upon one extremity of the iron. A strong magnetic action was 
now developed in the iron, much superior to that shown in any of 
the preceding experiments. The pole supporting the spiral coil was 
much superior in power to the other. 
5. The iron horse shoe was tlren covered with one hundred and 
thirty feet of the same ribbon. This was wound singly over the 
whole iron, and a spiral coiled around each pole, the two spirals be- 
ing coiled in different directions, and one containing about twenty 
five feet more than the other. This arrangement shewed consider- 
able magnetic power, but not quite as much as the last. The two 
coils being wound in different directions, nearly neutralize each 
other, and the only power gained is that produced by the excess in 
the length of one coil over the other. 
6. The same ribbon used in the last experiment, was coiled in 
two spirals, one around each pole of about equal size and wound in 
the same direction, and having the extremities of the ribbon in the 
center of each coil respectively. This produced the most powerful 
effect yet experienced, as the apparatus with the small. battery of 
eighteen inches and very feebly charged was capable of raising filty 
pounds. 
7. The whole apparatus was disposed as in the last experiment, 
only that the extremities of the ribbon in one coil proceeded from 
the center, and in the other from the circumference. This produ- 
ced the most powerful effect of all and with the same battery raised 
nearly twice the same weight. 
8. If the whole apparatus be arranged as in the last experiment, 
and another coil be placed upon the extremities of the iron, taking 
care that the current run in the same direction in both coils, upon 
connecting this with the same battery as the other coil, the power 
‘of the magnet will be greatly increased. 
Tt must appear evident to every one that the power of these mag- 
nets may be increased ad infinitum, by increasing the size of the horse 
shoe of soft iron, by increasing the width and length of the metallic 
ribbons, and also increasing the power of the battery: The effect 
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