232 EXPERIMENTAL INVESTIGATIONS. 



1. Into the bottom of a wineglass I cemented the bowl of 

 a tobacco-pipe ; into this was poured pure nitric acid, while 

 muriatic acid was poured into the wine glass to the same 

 level ; in this latter acid two strips of gold-leaf were allowed 

 to remain for an hour, at the end of which time they remained 

 as bright as when first immersed. A gold wire was now made 

 to touch the nitric acid and the extremity of one of the strips 

 of gold-leaf ; this was instantly dissolved, while the other 

 strip remained intact. 



2. The experiment was inverted, but offered some diffi- 

 culty, as the gold would not remain an equally long time in the 

 nitric acid, from the effect of the nitrous gas ; enough, how- 

 ever, was ascertained to prove that to the gold in this acid 

 contact made little or no difference ; while the gold in the 

 muriatic was always dissolved. 



3. A platina arc was used for connection instead of gold ; 

 the effect was the same. 



4. The outside of the pipe was coated with gold-leaf, 

 leaving scarcely any part exposed ; a strip was placed in the 

 muriatic acid as before, and when contact was made with the 

 nitric acid this strip was destroyed, while the coating of gold 

 directly across the line of junction was unhurt. 



5. The nitric acid was stained with a little tournesol ; when 

 contact was made, I could not see that the muriatic acid 

 acquired any of the colour. 



6. Nitrate of copper was used instead of nitric acid ; the 

 effect was the same, but took place more slowly, and I could 

 detect no precipitation on the negative metal. 



7. I now made gold-leaf in muriatic acid the electrodes 

 of a single pair of voltaic metals ; the acid was decomposed 

 and the positive electrode was dissolved. 



From all this I think we may pronounce the action to be 

 as follows : as soon as the electric current is established, both 

 the acids are decomposed, the Tiydrogen of the muriatic unites 

 with the oxygen of the nitric, and the chlorine attacks the gold. 



In all these cases the currents were examined with a gal- 

 vanometer, and in all the gold which was dissolved repre- 

 sented the zinc of an ordinary voltaic combination. The 

 greatest deflection was obtained with platina, gold, and two 



