2j50 ON THE COMPOSITION OF ALCOHOL. 



Method of I washed the inside of a large bladder with alcohol sevc- 



eomputing the ^.^j times, letting the alcohol stand in it a long time, to take 



dilatation of , • ■ . i • i 



▼apourof alco- Up everj'^ thing soluble in it, that this might not affect the 

 ^o'* expansibility. When this came out perfectly pure, the 



bladder was three parts filled with atmospheric air, two 

 ounces of alcohol were poured in, and it was stopped with a 

 cock. The air contained in it was dilated by the formation 

 of alcoholic vapour. At the expiration of eighteen hours I 

 fitted to the cock an empty receiver intended to weigh the 

 air. The cock being turned, the dilated air passed alone, 

 without any liquid alcohol, into the receiver, which was 

 • weighed before and after, the thermometer being at 17° [68" 

 r.], and the barometer at 26 inches 9 lines during these ope- 

 rations and those that followed. 

 Twice repeat- By this experiment, repeated twice under these circum- 

 '^' stances, I found, that 1000 cubic inches of atmospheric air di- 



lated by alcoholic vapour weighed 433'7fe grains; and 1000 

 inches of the air employed in the experiment weighed before 

 the introduction of the alcohol 424*5 grains. 

 Dilatation of "^^ measure the dilatation the air had undergone by the al- 

 the gas calcu- coholic vapour, I employed the formula of Mr. Dalton, and 

 D k i^'lf r- P*^ssed into a barometer a drop of alcohol, which sunk the 

 raula. barometer 20*5 lines, expressing the elastic force of the va- 



pour in 'vacuo. Applying this result to the formula — —» 



v—f 



where p= 26 inches 9 lines, and /z= 20*5 lines, we find, 

 that, the volume of undilated air being equal to 1, it be- 

 comes 1'0682 by the conversion of alcohol into vapour; and 

 as 1'0682 : 1 : : 1000 : 936-14, it may be inferred, that 1000 

 cubic inches of atmospheric air alcoholized contain 936*14 

 loOOcub in- of atmospheric air. These weigh 397*4 grains; and as the 

 cbesof alcoho' alcoholic vapour occupies the same space as the air dilated 

 weSi 3(3-38 ^Y ^^' ^^ follows, that 1000 cubic inches of pure vapour of 

 grs' ' alcohol weigh 433-78 — 397*4 = 36-38 grs. 



Vapours dif- I need not remind the reader, that, according to Dalton's 

 fuse themselvf s experiments, vapours diffuse themselves in the same quan- 

 in equal quaa- . ^ , . ,1^1 1 . 1 • 



tity whatever tity through every gas, that has no chemical action on 



the gas them*. I chose atmospheric air for finding the weight of 



Atmospheric * ^ ^^^P^ atmospheric air ia contact with alcohol a long time in a jar 

 air very slowly over mercuiv. In five months the air had uiidergoneno sensible change, 

 altered by al- y^^^ -^^ twelve it had lost -01 of oxigen gas. 



