Traiti Elementaire des Reactifs. 333 



ascertaining the proportion of alcohol in wines, beer, cider, &c., 

 long ago described by Mr. Brande, to 100 parts in volume of the 

 liquid : to be tried, 12 parts of solution of sub-acetate of lead * 

 are to be added ; a precipitation ensues - which is rendered general 

 by slight agitation. On filtering, a colourless fluid, containing the 

 alcohol, is procured. By mixing with this dry carbonate of potash, 

 (calcined pearl-ash,) as long as it is dissolved, we separate the 

 water from the alcohol. The latter is seen floating above in a 

 well-marked stratum; the quantity of which can be estimated at 

 once, in a measure lube. Suo-acetate of lead is also employed 

 for precipitating mucus in a flocky form, from its mixture with 

 gelatine, which is not affected by the salt. 



Borax, in coarse powder, or small lumps, is much employed 

 by the French chemists, for separating muriatic and sulphurous 

 acids from other gaseous bodies. 



To detect lime in sugar, muriate of ammonia in powder is mixed 

 with it, and heated. Pungent ammonia exhales. For the separa- 

 tion of alumina from its solution in an alkaline ley, sal ammoniac 

 is the proper re-agent. A muriate of potash is formed ; while the 

 ammonia and alumina are both disengaged. 



Under muriate of barytes, nothing is said, of the numerical 

 power of this test of sulphuric acid. According to Kirwan, a 

 solution of this salt produced a very sensible precipitation in 

 water that contained only ^^^.^ ' ^^ of real sulphuric acid. Ace- 

 tate of lead is ten times less sensible to this acid ; while nitrate 

 of lead, as well as nitrate and muriate of strontian, are far inferior 

 tests. When the acid is combined with a base, as in sulphate of 

 soda, the barytic salt is 1 1 times less sensible, even after two or 

 three hours of re-action, than with the free acid. According to 

 Bergman, solution of muriate of barytes immediatelt/ discovers 

 about -XTFTT ^^ combined sulphuric acid, or 3^133 in two or 

 three hours. The same test took twenty-four hours to detect one 

 grain of sulphate of lime in 6OOO of water. 



Where boracic acid is suspected to be mixed with sulphuric, 

 in a mineral water, muriate of strontian is a convenient re-agent, 

 as it throws down the latter without affecting the former acid. 

 In general, when muriate of barytes is applied to measure the 

 amount of sulphuric acid, we should digest the precipitate in 

 nitric acid of moderate strength ; then wash, dry, and ignite. Thus 

 the phosphate, borate, malate, tartrate, &c., will be removed. ' 



]\Iuriate of potash is prescribed for distinguishing tartaric from 

 citric acid ; for when it is added to a solution of the first, small 

 brilliant crystals of bitartrate of potash fall ; with the last acid, no 

 change ensues. 



• This solution is made by boiling 15 parts of pulverized (and calcined) 

 litharge, with 10 of acetate of lead, in 200 of water, for 20 minutes, and 

 concentrating the liquid by slow evaporation to one half; it must be kept 

 in well-corked phials, quite full. 



