120 
sively immersed never reached their maxima together, the effect of 
the earlier ones being lost before that of the later ones came on. 
In order to remedy this difficulty, he prepared eighty concentric i 
coils of copper and zinc plates and attached them to a system of 
levers so that they could be simultaneously immersed. The zinc 
sheets were nine inches by six in size, and the copper sheets four- 
teen inches by six, a quarter of an inch interval being left between 
them. Each pair, as rolled up, was two and a half inches in diam- 
eter, and eighty glass jars were arranged to receive the eighty coils 
of plates when they were lowered. A piece of charcoal a quarter 
of an inch thick and one and a half inches long was inserted be- 
tween the ends of the lead pipes which served as conductors. On 
lowering the plates ‘‘ no vestige of the charcoal could be seen. It 
was ignited so intensely that those portions of the pipes by which 
it had been embraced were destroyed.”’ 
He then had a trough constructed having a partition through the 
middle. In this trough he placed the eighty coils, forty of them 
being’ on each side of the partition. Although, when in action, 
this battery produced only a moderate sensation, and did not ignite 
charcoal as easily, a most intense ignition took place whenever a 
metallic point on one pole was brought in contact with a piece of 
charcoal on the other. And when a cylinder of platinum, nearly 
a quarter of an inch in diameter and tapering a little at the end, 
was placed in the circuit, it was at once fused and burned so as to 
sparkle to a considerable distance around and to fall in drops. 
When the two troughs were separated by an interval of four inches, 
so as to improve the insulation, charcoal was so vividly ignited that 
the eyes of the experimenter were affected for forty-eight hours, the 
charcoal assuming a pasty consistence. 
In accordance with the theory which he had propounded in 1818,* 
Dr. Hare explained these differences in effect by the hypothesis 
that the fluid extricated by Volta’s pile is a compound of caloric 
and electricity. According to this theory, ‘‘the galvanic fluid,’’ 
he says, ‘‘ owes its properties to caloric and electricity, the former 
predominating in proportion to the size of the pairs, the latter in 
proportion to the number, being in both cases excited by a power- 
ful acid. Hence in batteries which combine both qualifications 
sufficiently, as in all those intervening between Children’s large 
* Amer. Jour. Science and Arts, i, 418, 1818. 
