ON PYROXYLIC SPIRIT, &c. 115 



others, the excess beyond what was required for the secondary action was libera- 

 ted. This fact was more particularly determined in regard to a strong alcoholic 

 solution of potash, as will be afterwards noticed, and the analogy was suflBciently 

 obvious. The resinous, oily, or etherial matters were never found in sufficient 

 quantity to admit a more particular examination of them ; an observation which 

 applies equally to the formerly detailed experiments with alcohol. 



The extraordinary extent to which dissolved potash promotes the voltaic ac- 

 tion on alcohol and pyi'oxylic spirit, appears to be in part due to its disposing affi- 

 nity for the resinous or acid secondary products. 



As a farther proof that water was the true subject of the direct voltaic action, 

 an experiment was made with the volta-electrometer, as had been done in the case 

 of alcohol. The current from thirty-six pairs of 4 inch plates was passed through 

 pyroxylic spirit containing 555 part of potash dissolved, and also through water 

 containing the same quantity of potash, in the apparatus fig. 6. of former memoir, 

 the pyroxylic solution being placed in the bent tube sealed at the negative end. 

 Gas was evolved from all the poles except the positive of the spuit solution, and 

 at the end of 1 hour 5" there was found in 



N of the pyi-oxylic solution .10 cub. in. 



N of the aqueous solution .12 — — 



P of the aqueous solution .05 — — 

 Thus the quantities of hydrogen evolved from the two negative poles were suffi- 

 ciently similar in amount to confirm the view, that water in both cases was the 

 subject of decomposition. 



It being thus in the whole circumstances sufficiently clear, that when py- 

 roxyhc spirit is submitted to voltaic agency, water contained in the liquid is re- 

 solved into its elements by the direct operation of the current, it is conceived that 

 experimental proof is thus afforded that pyi'oxylic spirit, like alcohol, contains 

 water as an essential constituent. When allowance is made for the difference of 

 temperature at which the specific gravity of the spirit was taken by MM. Dumas 

 and Peligot and myself, the observed densities probably hardly differ ; and no 

 material variation on the natm-e of the action occuiTcd in the case of alcohol, un- 

 der much more considerable diversities of specific gravity. 



Since the substance in the pyroxylic series, corresponding to ether in the al- 

 cohol series, bears the gaseous form, I did not attempt to submit it to voltaic ac- 

 tion ; but I can hardly doubt that, had it been a liquid, the same analogy would 

 have been shewn in its electric relations, with respect to ether, as pyroxylic spirit 

 exhibited in regard to alcohol. Following out the general analogy between the 

 two series, I am inclined to adopt the same view in regard to the constitution of 

 the two liquids of the one series as with respect to those of the other ; and as it 

 appears to be sufficiently proved that pyroxylic spirit is a hydrate, it may be re- 



