On the Action of the Copper- Zinc Couple, 



285 







Al-Cu 



Al-Pt 



Temperature. 



Time. 



experiment. 



experiment. 







Hydrogen. 



Hydrogen. 







cub. centim. 



cub. centim. 



12 C. 



22 hours 



25 



4 



100 



next 6 „ 



375 



484 







92 



114 



it 





55 



78 



tt 



>> >> 



33 



45 



The action proceeded, at a diminishing rate, for several days. 



The fact brought out by the above experiments was further 

 established by other decompositions, and is of course corrobora- 

 tive of our work with zinc conjoined to more negative metals in 

 a spongy condition. 



XXXIII. Notes on the Action of the Copper-Zinc Couple. 

 By Professor Gladstone and Alfred Tribe*. 



Relative Activity of pure Zinc and Zinc covered with spongy 



Copper. 



A SOLUTION of sulphuric acid containing 3| parts of acid 

 to 1000 of water is just acted upon by pure zinc. 

 In an experiment with 2*5 grms. pure zinc (granulated) im- 

 mersed in this strength of acid, 7 volumes of hydrogen were given 

 off in one hour. 



In another experiment, in which the same piece of zinc upon 

 which "003 grm. of copper had been deposited was used, 80 vo- 

 lumes of hydrogen were given off in the same time. 



Thus it appears that the activity of zinc in very dilute sul- 

 phuric acid is increased elevenfold by 0*12 per cent, of the ne- 

 gative metal. 



Arseniuretted Hydrogen. 



If zinc containing arsenic act upon dilute sulphuric acid, the 

 hydrogen, as is well known, contains AsH 3 , the formation of 

 which is explicable (from analogy with what is known of the 

 action of hydrogen upon oxynitrogen compounds) on the supposi- 

 tion that the arsenic becomes dissolved, and that by the subse- 

 quent action of hydrogen upon the arsenical compound in solu- 

 tion the arseniuretted hydrogen is produced. 



Some four years ago we pointed out that the copper-zinc couple 



* Communicated by the Authors, having been read before the British 

 Association at Bristol, August 1875. 



