182 



EBULLITION ALCOHOLOMETER 



Saturated solution of carbonate of soda Griffiths . 220 



alum, containing 52 per cent. . 220 



,, , chlorate of potn si i, 40 . 218 



sulphate of copper, 45 .216 



EBVIiZiZTIOM* AXiCOHOXiOIVlETER. That the boiling temperature of water i,; 

 increased by holding neutro-salinc and saccharine substances in solution has been long 

 known, and has been the subject of many experiments, made partly with the view of 

 ascertaining from that temperature the proportion of the salt or sugar, and partly with 

 the view of obtaining a practical liquid bath. But it seems to have been reserved for 

 the Abbe 1 Brossard-Vidal of Toulon to have discovered that the boiling temperature 

 of alcoholic liquors is, in most cases, proportional to the quantity of alcohol, irrespec- 

 tively of the quantity of neutro-saline or saccharine matter dissolved in them. When, 

 however, such a quantity of dry carbonate of potash, or sugar, is added to a spirituous 

 liquor as to abstract or fix in the solid state a portion of the water present, then the 

 boiling temperature of that mixture will be lowered in proportion to the concentration 

 of the alcohol, instead of being raised, as would be the case with water so mixed. 

 But, generally speaking, it may be assumed as a fact, that the boiling point of an 

 alcoholic liquor is not altered by a moderate addition of saline, saccharine, or extrac- 

 tive matter. On this principle, M. Brossard-Vidal constructed the instrument repre- 



773 



Rented in fig. 772, for determining by that temperature the proportion of alcohol 

 present. His chief object was to furnish the revenue boards of France witli a means 

 of estimating directly the proportion of alcohol in wines, so as to detect the too 

 common practice of introducing brandy into their cities and towns under the mask of 

 wine, and thereby committing a fraud upon the octroi ; as the duty on spirits is mucli 

 higher than on wines. 



The above instrument consists of a spirit-lamp, surmounted by a small boiler, into 

 which a large cylindric glass bulb is plunged, having an upright stem of such calibre 

 that the quicksilver contained may, by its expansion and ascent when hea'ed. raise 

 before it a little glass float in the stem, which is connected by a thread with a similar 

 glass bead, that hangs in the air. The thread passes round a pulley, which turning 

 with the motion of the beads causes the index to move along the graduated circular 



