NOMOS. 13 



usually cited for the purpose. The quantity of 

 ordinary electricity, as will be shown presently, is 

 altogether insufficient to produce any marked results. 

 Gases are certainly evolved from the water, but 

 their quantity is too small to allow us to speculate 

 upon their nature so small that Dr. Faraday 

 " could not obtain at either pole a bubble of gas 

 larger than a small grain of sand," after working a 

 large machine for half an hour. We shall revert to 

 this point again ; but in the meantime sufficient has 

 been said to show that voltaic and ordinary electricity 

 agree in having, though in unequal degrees, the same 

 definite power of chemical decomposition. 



Ordinary electricity agrees with voltaic electricity 

 in being attended by the same shock when a strong 

 current is passed through the body, and the results 

 are not dissimilar when weaker currents are experi- 

 mented upon. " When," writes Dr. Faraday, " a 

 wet thread is interposed in the course of the current 

 of ordinary electricity from a battery charged by 

 eight or ten revolutions of a machine in good work- 

 ing order, and the discharge is made by platina 

 spatulas through the tongue or gums, the effect upon 

 the tongue and eyes is exactly that of a momentary 

 feeble voltaic current." 



Ordinary electricity agrees with voltaic electricity 

 in having light as one of the signs of the discharge. 

 The light of ordinary electricity is distinguished by 

 its instantaneousness, and by being accompanied 

 with a sharp explosive noise ; but if the discharge be 

 retarded by passing it through some wet string away 

 from the place where the spark has to pass, the light 



