AM^IONIA AND AMMONIACAL SALTS. 273 



If wine be evaporated upon a water bath, and con- 

 centrated to the thickness of syrup, the addition of 

 potash will always develope traces of ammonia, of 

 whatever kind the wine may be ; but the quantity 

 nevertheless appears to be very insignificant. 



Dobereiner endeavoured in another way to deter- 

 mine the presence of ammonia in wine, by distilling 

 the wine with potash, and adding chloride of platinum 

 to the distilled liquid. In the wines thus examined 

 by him, he detected ammonia ; but this method only 

 indicates the presence of a nitrogenous substance, 

 which yields ammonia when treated with potash ; and 

 such are both albumen and ferment extract, and the 

 existence of actual ammonia is by no means proved. 



P. 60, we mentioned a test used by De Saussure, 

 which required 0*81 grammes (12*5 grs.) of ammonia 

 to saturate the acids in 375 grammes (5787*7 grs.) 

 of must, whilst only 0'76 grammes (11'7 grs.) of 

 ammonia were necessary to neutralise the same quan- 

 tity of must, when it had been allowed to ferment 

 in a vacuum. The difference here = 05 (*8 grs.) 

 is insignificant, but De Saussure, like Dobereiner, 

 ascribes it to the formation of ammonia which they 

 think occurs daring fermentation. 



If now any one should imagine that during the 

 decomposition of the ferment of 375 grammes of must, 

 no more ammonia could be formed than is contained 

 in 0*05 grammes of sal-ammoniac, he would be much 

 mistaken. It was necessary to add 0'81 ammonia to 



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