1814.] Alcohol and Sulphuric Ether. 35 



of this gas are composed of 72-63 oxygen and 27"37 carbon : 100 

 parts of water by weight contain 88'3 of oxygen and 11'7 of 

 hydrogen, the volumes of these gases being to each other as two to 

 one. 



Section First. 



Analysis of Alcohol. 

 2. Decomposition of Alcohol by means of a red-hot Porcelain Tube. 



The analysis of alcohol by burning it in a lamp does not give a 

 correct result, because a portion of the liquid is volatilized without 

 undergoing combustion. When the vapour of alcohol, mixed with. 

 oxygen and hydrogen gas, is detonated in a eudiometer over mer- 

 cury at the temperature of the air, the combustion is complete ; 

 but the operation is very complicated, and the quantity wrought on. 

 is too small to entitle the result to any confidence. When alcohol 

 is distilled very slowly through a red-hot porcelain tube, it is almost 

 wholly converted into water and a gas, which may be analysed 

 without any difficulty. I have adopted this method, which is the 

 most exact of all those with which I am acquainted. 



The alcohol which I employed was prepared by mixing spirit of 

 wine with its own volume of water, and subjecting the mixture to 

 successive slow distillations, preserving only the portions which 

 passed over first in each. I obtained it of the specific gravity 

 0-8:302, at the temperature of 62-S° Fahrenheit. This result 

 indicates, according to the table of Richter,* a liquid composed of 

 13*8 water and bo -2 absolute alcoliol of this author, which I shall 

 denote by the name of alcohol of Richter. Its specific gravity is 

 0792, at the temperature of 68° Fahrenheit. 



The result of my analysis has been reduced by calculation to 

 what would have been obtained with the alcohol of Richter, because 

 that alcohol serves as the basis of the most copious and accurate 

 table that we have respecting the specific gravities of mixtures of 

 water and alcohol; but this base is not pure alcoliol, as Mr. Mutton 

 obtained an alcohol of the specific gravity 0*784, at the temperature 

 of 66°, which did not appear to be pure alcohol.f 



I employed an alcohol mixed with a good deal of water, and 

 rectified without the application of any saline substance, to guard 

 against the objections of those authors who are of opinion that 

 alcohol undergoes a chemical change by being concentrated accord- 

 ing to the process of Richter, by means of muriate of lime. This 

 alteiation, which may be a purification (since in depriving it of 

 water we separate those substances which arc only soluble in water), 

 is indicated by slight alterations in its flavour and smell, but occa- 

 sions no perceptible alteration in the analysis. When the two 



• Tlip correction which that (able reqolra was made from Gilpin'a tables. 

 + KxpcriuicutM on the congelation of alcohol by Mr. Button, llbl. Brit. 

 «ol. liij. 



c 2 



