180 Dr. Hare on a new Theory of Galvanism, [Sept. 



particles of the substances aft'ected . That no subtile fluid, such 

 as the matter of heat has been imagined to be, can be discharged 

 from these substances, in consequence of the effect of the elec- 

 tricity, seems probable, from the circumstance that a wire of 

 platina may be preserved in a state of intense ignition in vacuo, 

 by means of the voltaic apparatus, for an unlimited time ; and 

 such a wire cannot be supposed to contain an inexhaustible 

 quantity of subtile matter." 



But 1 demand where are the repellant and attractive powers 

 to which the ignition produced by the calorimotor can be attri- 

 buted ? Besides, I would beg leave respectfully to inquire of this 

 illustrious author, whence the necessity of considering the heat 

 evolved under the circumstances alluded to as the effect of the 

 electrical fluid ; or why we may not as well suppose the latter 

 to be excited by the heat? It is evident, as he observes, that a 

 wire cannot be supposed to contain an inexhaustible supply ef 

 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 igni- 

 tion produced by it was ascribed to electrical excitement. 



For the purpose of ascertaining the necessity of the alterna- 

 tion 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 succeed by 

 Dr. Patterson and Mr. Lukens, by means of two continuous 

 sheets, one of zinc, the other of copper, wound into two concen- 

 tric coils or spirals. This, though the circumstance was not 

 known to them, was the form I had myself proposed to adopt, 

 and had suggested as a convenient for a galvanic apparatus to 

 several friends at the beginning of the winter ; * though the 

 consideration above stated induced me to prefer for a first expe- 

 riment a more manageable arrangement. 



Since writing the above, I find that when, in the apparatus of 

 20 copper and 20 zinc plates, 10 copper plates on one. side are 

 connected with 10 zinc on the other, and a communication made 

 between the remaining 20 by a 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 galva- 

 nic pairs, excepting that there is no insulation, all the plates 



* Especially to Dr. T. P. Jones and Mr. Rubens Peale, who remember the 



sussrestion. 



