294 Mr. M. Donovan on the supposed Identity of the Agent 



without the smallest evidence of its presence. How different 

 would have been the result if even the smallest spark of common 

 electricity had acted on the leaves ! the attraction or repulsion 

 would be sufficient to destroy them by the mere mechanical vio- 

 lence of the effort. But, in point of fact, a voltaic arrangement 

 always renders one of the gold leaves positive and the other ne- 

 gative ; if the series be adequate, the gold leaves manifest a de- 

 cided attraction ; aud if in contact, will not separate without the 

 application of a countervailing force. Such an attraction and 

 adhesion I found to be evidenced by this differential electro- 

 meter, when the gold leaves were connected with so small a vol- 

 taic series as twenty pairs of plates, each three-quarters of a 

 square inch in surface, and arranged as a couronne des tosses. 



When we consider that, during the solution of the ziuc in the 

 foregoing experiment, no less than 2-10 millions of one-inch 

 sparks are supposed to have passed, that is, nearly 2,700,000 in 

 each second of time, the mind becomes bewildered by the incon- 

 ceivable velocity of such a succession ; and we cannot fail to be 

 struck with the quiet transit of a flash of lightning through the 

 gold leaves without melting them, or even producing the attrac- 

 tion or repulsion which a bit of excited sealing-wax would have 

 done. The passage of this quantity of electricity in this almost 

 instantaneous space of time through gold leaves, each weighing 

 the one-fiftieth of a grain, must produce such an enormous in- 

 tensity as would cause the dissipation of both, and the destruction 

 of the whole apparatus with an awful flash. 



Lest any should suppose that this quantity had been really 

 evolved, but had been dissipated or lost in some unaccountable 

 way, I made the following experiment, the result of which could 

 have been easily anticipated ; but simple as the experiment was, 

 I did not choose to use it as an argument without making it. 

 Two glass matrasses were procured, the necks of which were of 

 the same diameter, and could easily be joined into one continuous 

 straight neck by being melted at the lamp. Into one of these 

 was introduced a bit. of zinc-foil, of one inch by five-eighths sur- 

 face, weighing four grains, soldered to the edge of a piece of 

 copper double the surface of the zinc. The bottom of this 

 matrass was coated outside with tin-foil. Into the other matrass 

 was introduced dilute sulphuric acid, one-third of which by mea- 

 sure was concentrated acid. The two matrasses, held with their 

 necks horizontally, were now joined by melting at the lamp, so 

 that they were perfectly air-tight. This being done, and the 

 glass cold, the double matrass with its tin-foil coating was laid 

 on a condensing gold-leaf electrometer, and confined there in an 

 insulated state. The double matrass being now in a vertical 

 position, the acid ran down into the lower part which contained 



