Influence of Proportions in Electrolytes. 169 



posed. It consists of single proportionals of its elements, but 

 is not on that account an exception to the rule (679.), which 

 does not affirm that all compounds of single proportionals of 

 elements are decomposable, but that such as are decompos- 

 able are so constituted. 



688. Protochloride of phosphorus does not conduct nor be- 

 come decomposed. 



689. Protochloride of carbon does not conduct nor suffer 

 decomposition. In association with this substance, I sub- 

 mitted the hydro-chloride of carbon from defiant gas and 

 chlorine to the action of the electric current; but it also re- 

 fused to conduct or yield up its elements. 



690. With regard to the exceptions (679.), upon closer 

 examination, some of them disappear. Chloride of antimony 

 (a compound of one proportional of antimony and one and a 

 half of chlorine) of recent preparation was put into a tube 

 (Plate I. fig. 13.) (789.), and submitted when fused to the action 

 of the current, the positive electrode being of plumbago. No 

 electricity passed, and no appearance of decomposition was 

 visible at first ; but when the positive and negative electrodes 

 were brought very near each other in the chloride, then a 

 feeble action occurred and a feeble current passed. The 

 effect altogether was so small (although quite amenable to the 

 law before given), and so unlike the decomposition and con- 

 duction occurring in all the other cases, that I attribute it to 

 the presence of a minute quantity of water, (for which this 

 and many other chlorides have strong attractions, producing 

 hydrated chlorides,) or perhaps of a true protochloride con- 

 sisting of single proportionals (695. 796.). 



691. Periodide of mercury being examined in the same 

 manner, was found most distinctly to insulate whilst solid, 

 but conduct when fluid, according to the law of liquido-con- 

 duction (4*02.); but there was no appearance of decomposition. 

 No iodine appeared at the anode, nor mercury or other sub- 

 stance at the cathode. The case is, therefore, no exception 

 to the rule, that only compounds of single proportionals are 

 decomposable ; but it is an exception, and I think the only 

 one, to the statement, that all bodies subject to the law of 

 liquido-conduction are decomposable. I incline, however, 

 to believe, that a portion of protiodide of mercury is retained 

 dissolved in the periodide, and that to its slow decomposi- 

 tion the feeble conducting power is due. Periodide would be 

 formed, as a secondary result, at the anode; and the mercury 

 at the cathode would also form, as a secondary result, prot- 

 iodide. Both these bodies would mingle with the fluid mass, 

 and thus no final separation appear, notwithstanding the con- 

 tinued decomposition. 



Third Series. Vol. 5. No. 27. Sept. 18S4. Z 



