210 A new Theory of Galvanism. 



chemist observes, " When very small conducting surfaces are 

 used for convevingverv large quantities of electricity, they become 

 ignited ; and of the differet conductors that have been compared, 

 charcoal is most easily heated by electrical discharges*, next 

 iron, platina, gold, then copper, and lastly zinc. The phaenome- 

 na of electrical ignition, whether taking place in gaseous, fluid, 

 or solid bodies, always seem to be the result of a violent exertion 

 of the electrical attractive and repellent powers, which may be 

 connected with motions of the particles of the substances af- 

 fected. 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 electricity, seems probable, from 

 the circumstance, tliat a wire of platina may be preserved in a 

 state of intense ignition in vacuo, by means of the Voltaic appa- 

 ratus, for an unhmited time ; and such a wire cannot be sup- 

 posed to contain an inexhaustible quantity of subtile matter." 



But I demand, where are the repellent 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 a\itlior, 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 of 

 matter, however subtile ; but wherefore may not one kind of sub- 

 tile matter be supplied to it from the apparatus as well as an- 

 other? especiallv, when to suppose such a supply is quite as in- 

 consistent with the characteristics of pure electricitj', as with 

 those of pure caloric? 



It is evident from Mr. Children's paper in the Annals of Phi- 

 losophy, on the subject of his large apparatus, that the ignition 

 produced by it was ascribed to electrical excitement. 



For the purpose o^" ascertaining the necessity of the alternation 

 and proximity of the copper and zinc plates, it has been men- 

 tioned that distinct square sheets were employed. The experi- 

 ments have since been repeated and found to succeed by Dr. Pat- 

 terson and Mr. Lukens, by means of two continuous sheets, one 

 of zinc, the oth^T of copper, wound into two concentric 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 t; though the consideration above 



* The conclusions are drawn trom experiments made by the electricity of 

 the Voltaic apparatus. 



t Especially to Dr. T. P. Jones, and Mr. Rubens Pealc, who remember 

 the suggestion. 



stated 



