ON THE COMPOSITION OF ALCOHOL. ggj 



the vapour, because I could not employ pure oxlgen gas in 

 large quaiatity otherwise than at the point of extrememoisture; 

 and if it had got dry, or if the external air had any way 

 penetrated into the bladder, there would have been some 

 errour in the calculation of the weight. I repeated the ex- 

 periment however with oxigen gas, and found only a trifling 

 difference, which I ascribe to the causes just mentioned. 



To effect the combustion of alcoholic vapour, I prepared Alcoholic va- 

 alcoholized oxigen gas, by passing some drops of alcohol P""''"^'.''^ 

 into a jar filled with oxigen gas over mercury. I afterward gas 

 ■withdrew the superfluous alcohol, that could not rise in va- 

 pour, by introducing dry unsized paper, and taking it out 

 through the mercury, repeating this operation till the paper 

 came out perfectly dry, and then emptying the dilated gas 

 into a fresh jar, I had previously satisfied myself, that un- 

 sized paper would not condense the vapour of alcohol. 



This alcoholized oxigen gas was introduced into a Volta's would not de- 

 eudiometer filled with mercury, but 1 could not set it on fire ^o"^^"; ^Y the 

 by the electric spark. I was equally unsuccessful on adding 

 pure oxigen gas in various propovtions. The alcoholic va- 

 pour was too much rarefied in the oxigen gas to take fire, 

 "When I added a very small portion of hidrogen gas to the without a mix- 

 alcoholized oxigen gas, the electric spark produced complete ^"''^ °* hidro- 

 combustion of the alcoholic vapour. The same effect took oralittleliauld 

 place, when I substituted- an inappreciable quantity of alcohol. 

 liquid alcohol instead of hidrogen gas. The vesicular va- 

 pours, produced no doubt by this alcohol, answered the pur- 

 pose of hidrogen gas: but in an accurate experiment this 

 addition of liquid alcohol was inadmissible, as it was impos- 

 sible to ascertain its quantity. 



Accordingly to 500 parts by measure of alcoholized oxigen '^^^ expert- 

 ^- 1 , , r-.vi Pi-i . meat described. 



gas I added 99*2, or near a ntth, ot hidrogen gas, and de- 

 tonated the mixture. The combustion, taking a mean of 

 three experiments, gave a residuum, which, being analysed 

 by lime water and by Volta's eudiometer, contained 342*59 

 parts of oxigen gas, and 46*69 of carbonic acid gas. I omit 

 the nitrogen, which was found mixed in a small quantity with 

 the oxigen gas both before and after the combustion, and 

 acts no part that can be estimated. 1 must pbserve, that, 

 when I opened the eudiometer immediately after the detona- 



tiojfe 



