58 



OV SOME CHEMICAL AGENCIES 0* ELECTRICITY. 



Bttienl i'Ius- mediately proved, that another power must necessarily be* 

 t rat ions and ' , „ ... »,,'.. 



applications. concvrntMl ; tor it was not possible to refer the electricity 



exhibited by the opposition of metallic surfaces to any che- 

 mical alterations, particularly as the effect is more distinct in 

 a dry atmosphere, in which even the most oxidable metals do 

 not chan.e, than in a moist one, in which many metals un- 

 dergo chemical alteration. 



Other facts likewise soon occurred demonstrative of the 

 same thing. In the Voltaic combination of diluted nitrous 

 acid, zinc, and copper, as is well known, the side of the zinc 

 exposed to the acid is positive. But in combinations of zinc, 

 water, and diluted nitric acid, the surface exposed to the acid 

 is negative; though if the chemical action of the acid on the 

 zinc had been the cause of the effect, it ought to be the same 

 in both cases. 



In mere cases of chemical change likewise electricity it 

 never exhibited. Iron burnt in oxigen gas, properly con- 

 nected with a condensing electrometer, gives no charge to it, 

 during the process. Nitre and charcoal deflagrated in com- 

 munication with the same instrument do not by their agencies 

 in the slightest degree affect the gold leaves. Solid pure 

 potash and sulphuric acid made to combine in an insulated 

 platina crucible produce no electrical appearances. A solid 

 amalgam of bismuth and a solid amalgam of lead become 

 fluid when mixed together : the experiment, I find, is con- 

 nected with a diminution of temperature, but with no exhi- 

 bition of electrical effects. A thin plate of zinc, after being 

 placed upon a surface of mercury, and separated by an insu- 

 lating body, is found positive, the mercury is negative: the 

 effects are exalted by heating the metals; but let them be kept 

 in contact sufficiently long to amalgamate, and the compound 

 gives no signs of electricity. I could mention a great number 

 of other instances of pure chemical action in which I have used 

 all the means in my power to ascertain the fact, and the 

 result has been constantly the same. In cases of effervescence, 

 indeed, particularly when accompanied by much heat, the 

 metallic vessels employed become negative, but this is a phe- 

 nomenon connected with ctaporation, the change of state of a 



body 



