114 Hart's JS"cw Galvanic Apparatus, Theory, ^^c. 



Ii.ave not acted well without insulation, * was because 

 electro-caloric could retrocede in the negative, as well as 

 advance in the positive direction. I will now add, that 

 independently of the greater eifect produced by, the simul- 

 taneous immersion of my eighty coils, their power is im- 

 proved by the proximity of the surfaces, which are only 

 about an eighth of an inch asunder ; so that the circulation 

 may go on more rapidly. 



Pursuant to the doctrine, which supposes the same quan- 

 tity of electricity, varying in intensity in the ratio of the 

 number of pairs to the quantity of surface, to be the sole 

 agent in galvanic ignition, the electrical fluid as evolved by 

 Sir H. Davy's great pile, must have been nearly two thou- 

 sand times more intense, than as evolved by a single pair, 

 yet it gives sparks at no greater distance than the thirtieth or 

 fortieth of an inch. The intensity of the fluid must be at 

 least as much greater ia one instance, than in another, as the 

 sparks produced by it are longer. A fine electrical plate 

 machine (if thirty two inches diameter, will give sparks at 

 ten inches. Of course the intensity of tlie fluid which it 

 emits, must be three hundred times greater than that emit- 

 ted by two thousand pairs. The intensity produced by a 

 single pair, must be two thousand times less than that produ- 

 ced by a the great pile, and of course six hundred thousand 

 times less than that produced by a good electrical plate of 

 thirty two inches. Yet a single pair of about a square foot in 

 area, will certainly deflagrate more wire, than a like extent of 

 coated surface charged by such a plate. According to Sing- 

 er, it requires about one hundred and sixty square inches of 

 coated glass, to destroy watch pendulum wire ; a larger wire 

 may be burned off by a galvanic battery of a foot square. 

 But agreeably to the hypothesis in dispute, it compensates 

 by quantity, for the want of intensity. Hence tlie quantity 

 of fluid iu the pair is six hundred thousand times greater, 

 while its intensity is six hundred thousand times less ; and 

 vice versa of the coated surface. Is not this absurd ? What 

 does intensity mean as applied to a fluid ? Is it not expres- 

 sed by the ratio of quantity, to space ? If there be twice as 

 i^uch electricity within one cubic inch, as within another, is 



* That h, with the same mass of comlncling fluiJ, in contact with all the 

 surfaces, instead of being divided into diftereiit portions, each restricted ia 

 ils actiGtt to one copper and one ziac jibtc. 



