Page:Proceedings of the Royal Society of London Vol 1.djvu/337

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The object of the author is to determine how the greatest effect may be produced by the voltaic battery, with the least waste of power and expense.

For this purpose he had one battery constructed of twenty pairs of plates of zinc and copper of large dimensions, each plate being four feet long and two feet wide. Each pair was connected together only at the top by a strap of lead, so that both sides of each plate were exposed to the action of the ﬂuid in the trough. The trough was made entirely of wood, with wooden partitions, made water-ﬁght by cement; and this battery when in action was charged with a mixture of three parts nitrous acid, with one of sulphuric diluted with three parts of water.

With this battery,

1. Eighteen inches of platina wire-,‘T of an inch in diameter were fused in about twenty seconds.

2. Three feet of the same wire became visibly red by strong day-light.

3. Four feet of the same became very hot, but not visibly red.

4. Charcoal burned with intense brilliancy.

5. On iron wire, the effect was remarkably feeble. Not more than ten inches of the ﬁnest harpsichord wire could be fused by it.

6. Imperfect conductors were scarcely affected by it. No effect was produced upon barytes mixed with red oxide of mercury and water.

7. A gold-leaf electrometer was not affected by it.

8. The shock from this battery was scarcely perceptible.

The author‘s second battery consisted of 200 plates, about two inches square, placed in half-pint pots of common Queen's ware.

1. With this battery potash and barytes were readily decomposed.

2. The metallization of ammonia took place with great rapidity.

3. It visibly ignited charcoal.

4. It caused a strong divergence of the gold-leaf electrometer.

5. It gave vivid sparks for upwards of three hours, and was not exhausted till after forty hours.

The results of the foregoing experiments are considered as a conﬁrmation of Mr. Davy‘ s observation, that intensity increases with the number, and the guantity of electricity with the extent of the surface.

The effect of quantity is seen in the ﬁrst experiment on platina wire. This metal not being oxidated presents no obstacle to the passage of the electricities, Which evolve. on their mutual annihilation, heat sufﬁcient to raise the temperature of the platina to the point of fusion.

Nevertheless from want of intensity, this quantity could not ﬁnd a ready passage through the suboxidated iron wire, and could produce no effect upon barytes or other bodies liable to be decomposed by