+ 
418 Hare’s Calorimotor. 
observes, that a wire cannot be supposed to contain an inex- 
haustible supply of matter however subtile; but wherefore 
may not one kind of subtile matter be supplied to it from the 
apparatus as well as another ; especially, when to suppose 
such a supply is quite as inconsistent with the characteristics 
of pure electricity, as with those of pure caloric ? 
It is evident from Mr. Children’s paper in the Annals of 
Philosophy, on the subject of his large apparatus, that the 
ignition produced by it was ascribed to electrical excitement. 
For the purpose of ascertaining the necessity of the alter- 
nation and proximity of the copper and zinc plates, it has 
been mentioned that distinct square sheets were employed. 
The experiments have since been repeated and found to suc- 
ceed by Dr. Patterson and Mr. Lukens, by means of two con- 
tinuous sheets, one of zinc, the other of copper, wound into 
_ two concentric coils or spirals. This, though the circum- 
stance was not known to them, was the form I had myself 
proposed to adopt, and had suggested as convenient for a Gal- 
vanic apparatus to several friends at the beginning of the win- 
ter;* though the consideration above stated induced me to 
prefer for a first experiment a more manageable arrange- 
ment. , etic a 
Since writing the above, I find that when, in the apparatus 
of twenty copper and twenty zinc plates, ten copper plates on 
one side are connected with ten zinc on the other, and a 
communication made between the remaining twenty by @ piece 
of iron wire, about the eighth of an inch in diameter, the wire 
enters into a vivid state of combustion on the immersion of 
the plates. Platina wire equal to No. 18 (the largest I had at 
hand) is rapidly fused if substituted for the iron. 
This arrangement is equivalent to a battery of two large 
Galvanic pairs; excepting that there is no insulation, all the 
plates being plunged into one vessel. I have usually separated 
the pairs by a board, extending across the frame merely. 
Indeed, when the forty plates were successively associated 
in pairs, of copper and zinc, though suspended in a fluid he 
* Especially to Dr. T. P. Jones, and Mr. Rubens Peale, who remember 
the suggestions. 
