64 ALCOHOLOMETRT 



bubbles of air out of the liquid. By now observing the dilatation of the column 

 of liquid when the temperature of the whole apparatus is raised, by immersion 

 in a water-bath, from 25 to 60, the co-efficient of expansion of the liquid is 

 obtained, and hence the proportion of alcohol the instrument being, in fact, eo 

 graduated, by experiments previously made upon mixtures of known composition, as 

 to give at once the per-centage of alcohol. 



Another alcoholometer, which, like the former, is more remarkable for the groat 

 facility and expedition with which approximative results can be obtained than for 

 a high degree of accuracy, was invented by M. Geisler, of Bonn, and depends upon 

 the measurement of the tension of the vapour of the liquid, as indicated by the 

 height to which it raises a column of mercury. 



Geialer's Alcoholometer. It consists of a closed vessel in which the alcoholic mix- 

 ture is raised to the boiling point, and the tension of the vapour ob- 

 served by the depression of a column of mercury in one limb of a tube, the 

 indication being rendered more manifest by the elevation of the other end 

 of the column. 



The wine or other liquor of which it is desired to ascertain the strength, 

 is put into the little flask, F, which, when completely filled, is screwed 

 on to the glass which contains mercury, and is closed by a stopcock at s. 

 The entire apparatus, which at present is in an inverted position, is now 

 stood erect, the flask and lower extremity of the tube being immersed in 

 a water-bath. The vinous liquid is thus heated to the boiling point, and 

 its vapour forces the mercury up into the long limb of the tube. The 

 instrument having been graduated, once for all, by actual experiment, 

 the per-centage of alcohol is read off at once on the stem by the height to 

 which the mercurial column rises. 



To show how nearly the results obtained by this instrument agree 

 with those obtained by the distillation process, comparative experiments 

 were made on the same wines by Dr. Bence Jones. 1 



By Distillation (Mr. Witt) By Alcoholometer 

 per cent, by measure. per cent, by measure. 



Port, 1834 ..*.'. . . 22-46 . . -f^ 



f207 



Sherry, Montilla 19-95 . < 20-6 



L20-6 



Madeira 22-40 . 



Haut Brion claret . . . . 10-0 . . 



Chambertin 117 . . -, g . 



Low-quality sherry .... 207 . . \^l-g 



Brown sherry 23-1 



21-0 



Amontillado . . . . . 20*5 



Mansanilla ...... 14-4 



Port, best 20-2 



Marcobrunner . . . . . 8-3 



Home ale 6-4 



Export ale ...... 6-4 



Strong ale ...... 2-0 



21-0 



15-4 



15-4 



21-1 



21-0 



97 



9-5 



7-0 



7-1 



7-0 



6-9 



107 



10-8 



Tobarie'8 Method. There is another method of determining the alcoholic contents 

 of mixtures, which especially recommends itself on account of its simplicity. The 



1 On the Acidity, Sweetness, and Strength of different Wines, by H. Bence Jones, M.D., F.B.S. 

 Proceedings of the Boyal Institution, February, 1851. 



