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LIV. Method of obtaining inodorous Benzoic Add. Bv 

 JM. F. GiESE*. 



X H E benzoic acid, fuch as we obtain it in the dry or 

 humid way, always retains a peculiar ftrong agreeable odour, 

 which has hitherto been confidered as a particular chara(Ster 

 of this acid. The numerous experiments I have made on 

 this acid {liow that chemifts in this refpeft have been in 

 an error, and that the benzoic acid may be deprived of all its 

 odour without injuring its principles or altering its nature. 



I was led to this obfervation by remarking, that the fame 

 acid extrafted from the urine of graminovorous animals, 

 when deprived of all urinous odour, is perfectly inodorous. 

 This circumftance induced me to believe that the odour of 

 the benzoic acid might be foreign to it ; and to afcertain this 

 fa6l I made the following experiments : 



I united odorous benZ' ic acid to a folution of potafh, and 

 then precipitated by muriatic acid. On each repetitionof the 

 experiment the odour was feniibly dinnnidied, and after the 

 third it had totally difappeared. 



As the acid retained all its characters, this feems to prove 

 that in thefc operations it had experienced no particular mo- 

 dification f. This refult was previoufly indicated by its ac- 

 quiring, in the progrefs of the experiment, the odour of ben- 

 zoic acid obtained in the humid way, which is much weaker 

 than that of the fame acid obtained by fublimation. 



I afterwards invented another method, more dire6l and 

 Icfs troublefome, for depriving this acid of its odour. It is 

 founded on the greater folubillty of the benzoic acid in fpirit 

 of wine than in water; and on the folubility of the benzoic 

 oil, which is the principle of ils odour, in diluted fpirit of 

 wine. This method is as follows: 



Diflblve benzoic acid in as fmall a quantity as poflible of 

 fpirit of wine : filter the folution, and drop water into it until 

 no more precipitate is formed, or until the precipitate formed 

 begins to be rediflolved. Separate the liquor by filtration, 

 and dry the acid, which remains on the filler, at a gentle 

 heat. 



* From Schcrer's Aligcmeines Journal der Chimlet February and March 



lf,02. 



I r can certify that a fpecimen of this acid, fhown to me by the an- 

 thor, was abfoluttly free fioin odour. I requelled M. Gitff to lubjcdt the 

 inodorous ;;cid to lublimatioii, in ordtr to afccrtaiti whcthvr a deiompofi- 

 fion experienced by tl« heat was not tlic caufc of its odour. He complied 

 with my rt<|vicft ; but be obl'erved no altciatioD in the acid, nor had it ic- 

 fuiTicd itk odour. — Schekkk. 



I (Iiall 



