concerned in the Phenomena of ordinary Electricity, tfe. 209 



to the negative conductor of a common electrical machine. The 

 agent in both cases runs, or rather flies, with a rapidity which 

 surpasses all comprehension, and, as far as we know, with equal 

 rapidity in both. In my experiment with common electricity, 

 the current was as abundant and rapid as it could be imagined 

 to be in the case of the voltaic combination of the wires with 

 gold-leaf; for the coil of the galvanometer was maintained per- 

 manently as full in all parts as it could contain. The current 

 passed as rapidly through the coil as the wire could transmit it 

 from the positive to the negative conductor of the electrical ma- 

 chine. In what way can a more rapid current be conceived ? 

 In fine, it is difficult to comprehend how the quantity could be 

 less in the experiment with statical electricity, when the indica- 

 tions of its presence were infinitely greater ; and as to the greater 

 rapidity of motion of the current, sometimes claimed in the case 

 of the voltaic combinations, it is but an assumption unsupported 

 by any known fact, and contradicted by everything we know of 

 the electric fluid. I shall hereafter have to consider more fully 

 the peculiarities attributed to current electricity. 



The failure of a common galvanometer to produce deflections 

 with frictional electricity, is explained by Colladon by the lateral 

 overflow of electricity from one layer to another, in consequence 

 of the surcharge of the coil. The inference therefore is, that 

 deflections are produced by a minute pair of voltaic elements, 

 such as I employed, because there is no such surcharge or over- 

 flow. Can this explanation be admitted, when it is considered, 

 that although the coil may overflow with common electricity, it 

 must retain at least its full quantum of charge ; and that is all 

 it can derive from the minute pair of voltaic elements, if it can 

 derive so much? The coil is therefore under at least equal cir- 

 cumstances in both cases; why then is there in one case deflec- 

 tion, and in the other none ? I know of no answer, unless it be 

 received as one, according to the suggestion given in the com- 

 mencement of this essay, that the agent in the former was elec- 

 tricity, which contained the maximum of the deflecting elementary 

 constituent ; and that in the latter the agent was electricity with 

 its natural minimum of the deflecting constituent, because it was 

 developed by mere friction. Hence the necessity of the presence 

 of Mich electricity in considerable quantity and intensity to pro- 

 duce the required effect. 



J made an experiment which appears to be explicable in the 

 same manner, although it is a difficulty in the way of the popu- 

 lar hypothesis. I selected a galvanometer the astatic needle of 

 which weighed 60 grs. With the. ends of iis coil I connected a 

 platinum and a zinc plate, by platinum wires ; the platinum 

 plate was halt' a superficial inch square; the zinc plate, made of 



Phil. May. S. 1. Vol. 13. No. 17. March 1852. P 



