and Attached Water, 27 1 



research is prefixed to a recent paper on the subject by M.Melsens, 

 in the Annates ds Chimie et de Physique, entitled " Sur la refroi- 

 dissement et la congelation des liquides alcoholiques et des vins." 

 According to M. Boussingault, frozen wines after thawing fur- 

 nish an alcoholic liquid and are not therefore pure ice. Accord- 

 ing to M. Melsens, alcoholic liquids containing about 50 per 

 cent, of alcohol by weight or by volume become at— 30°C. viscid, 

 syrupy, and sometimes opalescent. These represent commercial 

 spirits such as rum, cognac, &c, and may be represented by the 

 formula C 2 H 6 + 3 H 2 0, corresponding to the maximum con- 

 densation. According, again, to M. Melsens, when wine which 

 has become semisolid through being exposed to cold of a free- 

 zing-mixture is drained through wire gauze or introduced into a 

 turbine, nearly colourless ice free from alcohol is left. From 

 frozen wine containing from 10 to 12 per cent, of alcohol, from 

 16 to 25 per cent, of pure ice was got by means of a screw press. 

 By the same means a frozen red or white Burgundy yielded 40 

 per cent, of ice. 



§ 93. In the first of a series of able researches on the physical 

 properties of mixtures of water with the alcohols, Messrs. Dupre 

 and Page (Proc. Boy. Soc. March 11, 1869) examined, amongst 

 others, the quantity of heat developed on mixing alcohol and 

 water in various proportions, the specifie heat of such mixtures, 

 their capillarity, boiling-point, and their compressibility. 



The following fragments of these experimenters' Tables include 

 the critical values. 



Table showing number of heat-units evolved from 5 grammes of 

 mixtures resulting from mixing the percentages by weight of 

 alcohol in column 1 with the complementary percentage of 

 water. The asterisk shows the critical region. 



, t i i Heat-units from 5 arms, 



per cent, alcohol. of mixture. 



10 26-68 



20 43-95 



30 47-98* 



40 44-86 



45 38-81 



In the next Table Messrs. Dupre and Page's numbers are 

 given, showing the specific heats of such mixtures. The column 

 1 shows the percentage of alcohol, column 2 the specific heat, 

 column A the difference between the observed and calculated 

 specific heats. 



