128 



Mr. Drinkwater on the Preparation of 



Alcohol. Water. 



100 + 80-9847 

 100 -8.336 



Specific gravity. 

 •91930 

 54 



Add water 



Proof-spirit = 100 + 81-8183 -91984 



From the foregoing data the following results have been 



calculated : — 



Composition of Proof-Spirit. 



It is remarkable that Dr. A. Steel * arrived at almost the 

 same composition for proof-spirit, namely, 49-2 and 50-8, 

 partly by expei-iment and partly by calculation. 



The table of M. Lowitz, showing the quantity of alcohol 

 in spirits of different specific gravities (which is to be found 

 in most chemical works published in this country), also agrees 

 with these experiments at this particular point, although from 

 some experiments which 1 have had occasion to make, I have 

 found that at other points this table is incorrect ; and as it is 

 frequently consulted by chemists, it was considered desirable 

 to make a few mixtures of pure alcohol and water, from which 

 to calculate a more correct table for estimating the quantity 

 of alcohol in mixtures containing not more than 10 per cent, 

 of that liquid. 



Eleven mixtures wei-e therefore made, containing exactly 

 i, 1, 2, 3, 4, 5, 6, 7j 8, 9 and 10 per cent, by weight of abso- 

 lute alcohol. These mixtures were made in the same appa- 

 ratus, and with all the precautions described in the former ex- 

 periments. They were allowed to stand at least 24 hours with 

 occasional agitation before the specific gravities were taken, 

 and several of them were again taken after a period of 48 

 and 72 hours, without any sensible variation. 



The particulars are set forth in the following table : — 



* Dr. Steel's papers, which contain much valuable information on the 

 specific gravity of spirits, are contained in the ' Records of General Science,' 

 vol. i. pp. 222-255. 



