Mr. Warington on Chromic Acid in Voltaic Arrangements. 393 



3 atoms of oxide of Cacodyl, Cj2 Hig Asg O3 

 2atomsofC4H6 Cg H^, = 4CH, + 4CH 



C4 He Asg O3 



The rational constitution of this compound can only be con- 

 jectured. As cacodyl in combination with oxygen undergoes 

 the same decomposition at a higher temperature as in an un- 

 combined state, it follows that erytrarsin may be considered as 

 the oxide of a ternary radical, which can be distinguished 

 from cacodyl only by its containing three times as much 

 arsenic. The complete examination of such a substance 

 would be attended with great danger and many difficulties. 



LVIII. On the employment of Chromic Acid as an Agent in 

 Voltaic Arrangements. By R. Warington, Esq.^ 



IN a paper " On the Action of Chromic Acid upon Silver," 

 published in the Philosophical Magazine for December 1 837, 

 which action was effected by means of a mixture of bichromate 

 of potash in solution and sulphuric acid, I concluded by stating, 

 that in a future communication I hoped to consider the action 

 of the same agents on other metallic bodies. The investiga- 

 tion has been resumed when my engagements permitted, and 

 a great variety of interesting facts on this subject collected ; 

 but many analyses will still be necessary to render the subject 

 complete, before the whole results can be submitted to the 

 scientific world. 



On making some new experiments, some time since, with 

 the mixture of bichromate of potash and sulphuric acid re- 

 ferred to, I was led to believe that it would form a valuable 

 and powerful agent in voltaic arrangements from possessing 

 the following advantages over every other liquid hitherto em- 

 ployed for the same purpose, namely, the high degree of 

 energy with which it acts upon certain metals, the facility with 

 which it is decomposed by deoxidizing agents, as hydrogen 

 gas and numerous others, with the circumstance that in all 

 these actions of oxidation no gaseous matter is evolved. 



My first endeavour was to substitute this mixed fluid for 

 the nitric acid in the powerful arrangement of Professor 

 Grove, so as, if possible, to obviate the inconveniences arising 

 during tile action of that battery, without diminishing the 

 splendid effects produced by it. In doing this it was abso- 

 lutely necessary, from the nature of the materials to be em- 

 ployed, to modify to a certain extent the details of the con- 

 struction of the battery, retaining the metallic elements unal- 

 tered, but enlarging considerably the cell appropriated for the 



• Communicated by the Chemical Society, having been read Dec. 7, 1841. 



