480 On the Strengths of the Mixiutes of Alcohol, 



Notwithftanding the regularity of the tables of Briflbn and Gouvenain, Clt. Hafl'enfratz 

 was obliged to reject them in his farther proceedings, becaufe thofe cf Briffon were made 

 at one temperatme only i and from the very uniform courfe of the differences in thofe of 

 Gouvenain, he faw reafon to conclude, that they muft have been made by interpolation 

 between few and diftant experin>ents. Re' gives, neverthelefs. tabulated abftrafts of their 

 refults. The Royal Society's experiments publiflied by Sir Charles Blagden, are confe- 

 quently the foundation of his conftrudion of an alcograde. 



If from thefe experiments curves be traced, exprefling the denfities of the (everal com- 

 binations of water and alcohol taken at different temperatures, he obferves, that with re- 

 gard to alcohol and its feveral combinations, as low as nine parts of alcohol, and one of 

 water, the denfity follows the inverfe proportion of the temperature, and the curve 

 becomes a flrait line ; but that every lefs proportion of alcohol follows a different inverfe 

 proportion ; that is to fay, tlie line which paffes through the extremities of the ordinates, 

 is a curve of which the radius at curvature is longer the greater the proportion of water. 



After fome difcuffion of the method of forming the combinations by weight and by 

 meafure, the firft of which has the great advantages of accuracy and facility of experiment, 

 with regard to thofe operations which require change of temperature *, and the latter pof- 

 feffes that of being more accommodated to the commercial habits of fociety; Citizen H. 

 makes fome obfervarions on the difference between brandies, and the mixtures of alcohol 

 and water. Brandy, fays he, is the produft obtained by dillillation from a vinous liquor, 

 in which the atlion of fire changes the order of the component parts, and carries over this 

 fluid : alcohol is the produ£l: of a fecond operation of the fame nature, in which fimilar 

 effects are produced upon the brandy. In proof of the force of this method of confideiing 

 the fubjett, he remarks, that the brandy will not again form wine by mixing it with the 

 refidue left in the ftill : neither will the alcohol form brandy by mixture with the refidue, 

 from which it was produced and driven over. 



The differences of the vinous fluids in denfity above or below that of water, in flavor, 

 and other obvious characters, are extreme ; and the brandies from wine properly fo called, 

 from beer, perry, cyder, &c. are no iefs remarkable for their peculiar qualities. All thefe 

 afford alcohol, which has been fuppofed to be then the fame fluid ; but our author confi- 

 ders thefe alfo as differing in their immediate and intrinfic qualities. The alcograde is in- 

 fufficient for the (tricl exhibition of the variations of thefe with water, and moft obviouily 

 withrefpe6): to brandies, of which the price is governed fo much by qualities and circura- 

 ftances, not at all commenfurate with their fpecific gravities. For wines, beer, and other 

 immediate produds of fermentation, this method of examination does not appear to be of 

 any ufe. 



He admits, neverthelefs, that the alcograde is beft adapted of any inftrument for giving' 

 that approximate indication of value which the tranfadions of life demand. He propofes 

 the conftrudiion of a floating inftrument, which (hall (hew the proportion of alcohol by 

 jnfpedtion at any known temperature by graduation. The following table, is de- 

 rived 



