96 Hygromelric Properties of Insoluble Compounds. 



Known weights of these various specimens of paper, dried 

 strongly before a fire, were exposed to the atmosphere for 24 

 hours, and gained the annexed increase for every 100 parts. 



The respective quantities of moisture, absorbed by all the sub- 

 stances, may very probably vary according to the method of their 

 preparation and state of mechanical division, but as far as gene- 

 ral results are concerned, they will not differ very widely from 

 the above. 



Art. X.—On the Production and Nature of Oil of Wine, 

 (Oleum JSthereum of the London Pharmacopoeia,) by 

 Mr. H. Hennell, Chemical Operator at Apothecaries* 

 Hall. 



[Communicated by the Author.] 



Mr.R. Phillips, in his translation of the London Pharmacopoeia, 

 appearing to doubt the existence of Oil of Wine, as a distinct 

 substance, I was induced carefully to repeat the process we 

 usually adopt in our laboratories for obtaining it. 



Half a gallon of rectified spirit of wine (Sp. Gr. 830,) was 

 mixed with an equal bulk of sulphuric acid, and distilled in a 

 glass retort ; the products were ether, water, sulphurous acid, and 

 about four ounces of a yellow fluid floating upon the water, 

 which, when separated and washed with solution of carbonate of 

 potash as long as there was any trace of sulphurous acid, was 

 a solution of true oil of wine in ether. The ether may be re- 

 moved, either by spontaneous evaporation, or it may be distilled 

 oflf with a very gentle heat. The oil thus obtained, and which 

 amounts to about two ounces, is a yellow fluid, resembling, in 

 appearance, oil of lavender or peppermint ; perhaps rather more 

 viscid. It has a specific gravity of 1.05. After being kept a 

 few months, it becomes more viscid, and a number of prismatic 

 crystals form in it, which, in many of their characters, very much 



