1819.] and a new Galvanic Instrument. 177 



The grounds of this conviction and some recent experiments 

 confirming it are stated in the following paper. 



It is well known that heat is liberated by voltaic apparatus in 

 a manner and degree which has not been imitated by means of 

 mechanical electricity ; and that the latter, while it strikes at a 

 greater distance, and pervades conductors with much greater 

 speed, can with difficulty be made to effect the slightest decom- 

 positions. Wollaston, it is true, decomposed water by means of 

 it ; but the experiment was performed of necessity on a scale too 

 minute to permit of his ascertaining whether there were any 

 divellent polar attractions exercised towards the atoms, as in the 

 case of the pile. The result was probably caused by mechanical 

 concussion, or that process by which the particles of matter are 

 dispersed when a battery is discharged through them. The 

 opinion of Dr. Thomson, that the fluici of the pile is in quantity 

 greater, in intensity less, than that evolved by the machine, is 

 very inconsistent with the experiments of the chemist above- 

 mentioned, who, before he could effect the separation of the 

 elements of water by mechanical electricity was obliged to con- 

 fine its emission to a point imperceptible to the naked eye. If 

 already so highly intense, wherefore the necessity of a further 

 concentration ? Besides, were the distinction made by Dr. Thom- 

 son correct, the more concentrated fluid generated by a galvanic 

 apparatus of a great many small pairs, ought most to resemble 

 that of the ordinary electricity ; but the opposite is the case. 

 The ignition produced by a few large galvanic plates, where the 

 intensity is of course low, is a result most analogous to the 

 chemical effects of a common electrical battery. According to 

 my view, caloric and electricity may be distinguished by the 

 following characteristics. The former permeates all matter more 

 or less, though with very different degrees of facility. It radiates 

 through air, with immeasurable celerity, and distributing itself 

 in the interior of bodies, communicates a reciprocally repellent 

 power to atoms but not to masses. Electricity does not radiate 

 in or through any matter ; and while it pervades some bodies, as 

 metals, with almost infinite velocity ; by others, it is so far from 

 being conducted that it can only pass through them by a fracture 

 or perforation. Distributing itself over surfaces only, it causes 

 repulsion between masses, but not between the particles of the 

 same mass. The disposition of the last mentioned principle to 

 get off by neighbouring conductors, and of the other to combine 

 with the adjoining matter, or to escape by radiation, would pre- 

 vent them from being collected at the positive pole, if not in 

 combination with each other. Were it not for a modification of 

 their properties consequent to some such union, they could not, 

 in piles of thousands of pairs, be carried forward through the 

 <jpf:n air and moisture; the one so well calculated to conduct 

 away electricity, the other so favourable to the radiation of 

 pali ric. 



Vol. XIV. N° III. M 



