FERMENT OILS. 375 



147^ C. (barometric pressure 735 m. m.), but the mercury soon rose 

 to 150*^ C, and the distillation was conducted between 150^ and 

 160^ C. After about four hours, the liquid in the flask became 

 quite thick and was thoroughly carbonised. As no more liquid 

 distilled over at the above-mentioned temperature, and a strong 

 current of sulphur dioxide was evolved, owing to the reduction 

 of the sulphuric acid by the carbonaceous matter, the operation 

 was discontinued. The ethereal distillate was treated as directed 

 in the ofhcial process, when 2;5 grams of pure heavy oil of wine, or 

 0'597 per cent, of the weight of alcohol employed was obtained. 

 This is somewhat less than Dr. Squibb has stated to have obtained 

 in working upon a larger scale, for in a series of distillations with 

 a total use of 1664 pounds of sulphuric acid, and 686 pounds of 

 alcohol, he obtained 97 avoirdupois ounces of finished oil, or 0-884 

 per cent, of the weight of alcohol employed.* The yield obtained 

 by Prof. Diehl, in the U.S. Army Laboratory seems to have been 

 considerably higher (about 1-4 to 1-9 per cent.) although he 

 employed the same proportions of alcohol and acid (equal parts by 

 volume) as are directed in the U.S. official formula.! 



In the process of the British Pharmacopoeia, it is evidently 

 assumed that the yield of heavy oil of wine shall be about 1 per 

 cent. l)y volume, at least, of the alcohol consumed, for 3 fluid 

 drachms of the oil are directed to be used, and this is to be obtained 

 from 40 fluid ounces, or 320 fluid drachms of rectified spirit. The 

 yield stated by Dr. Squibb of 0*884 per cent, by w^eight, corresponds 

 to 0*684 per cent, of the alcohol by volume. Dr. Power states, in 

 his paper above referred to, that, after reviewing the existing 

 knowledge of so-called heavy oil of wine, "it is clearly evident 

 that the oleum ccthereum of the Pharmacopoeia is an exceedingly 

 unsatisfactory preparation, not only with consideration of its small 

 yield, but more especially on account of its indefinite and probably 

 variable chemical character, and the complete lack of information 

 as to which of its constituents represents its assumed medicinal 

 virtues." Also, — " it has been shown that the heavy oil of wine 

 or ethereal oil of commerce, is, for the most part, a by-product in 

 the manufacture of ether, and is a liquid of entirely difterent 

 chemical composition from that produced by the process of our 



* Am. Journ. Phann., 1861, p. 60. 

 t Ibid, 1865, pp. 100 and 126. 



