125 On the Analyfis of IVirie. 



ititric acid ought to have difcngaged and oxygenated the fame 

 quantity of muriatic acid. I confefs that 1 cannot conceive 

 how an excels of marine fait or nitrate of foda, found in the 

 mixture, could prevent the folution of a greater quantity of 

 crude plalina, unlefs the explanation of this phcenomenon 

 be founil in an obfervation I fliali here make, or my occu- 

 pations; allow me to undertake new refearches on this iubje^l. 

 The obfervation I allude to is as follows: The refiduuin 

 of all the folution?, that is to fay, the remaining crude pla- 

 tina, exhibits an afpeiSt very diflerent from that of the reli- 

 duums left by nitro -muriatic acid couipofed of free acids. 

 [The airthor promifes a continuation of thefe experiments.] 



XX. On the Analyfis of Wine. By C. Chaptal" 



I 



N all wines we diftinguiOi an acid^ alcohol, tartar, ex- 

 traftive matter, aroma, and a colouring principle; the whole 

 diluted or difTolved in a portion of water more or lefs abun- 

 dant. 



ill. Acid. — An acid exifts in all wines ; I never found any 

 which did not prefent fome traces of it. The fweelcft anil 

 moft lufcious wines redden tell paper, if fufl'ered to remain in 

 them for fome time ; but they are not all acid in the fame 

 degree. There are fome the principal chara6ter of which is 

 a natural acidity. Thofe made from grapes not perfe^lly 

 ripe, or produced in cold climates, are ot this fort; while 

 thofe produced by the fermentation of very ripe and faccha- 

 rine grapes exhibit very little acid. The acid, then, appears 

 to be in the inverfe ratio of the alcohol, wliieh is the relult 

 of the dccompofiiion of the fugar. 



This acid exifts in great abundance in verjuice; and is found 

 in mull, though in a fmaller quantity. All fermented liquors, 

 fuch as cyder, perry, and beer, as well as fermented farina- 

 ceous fubdances, alfo contain this acid : and I have found it 

 even in molaflt'S. Indeed it is to faturate it completely, that 

 lime, allies, or other earthy or alkaline bafes, are obliged to 

 be employed in the purification of fugar. Without this pre- 

 caution, the exillence of the acid would oppofe the crylial- 

 llzalion of the fugar. 



If wine be concentrated by dillillation, the extratl which 

 rcfults from it in general has a four and pungent talle. Ta 

 diflblve and feparate the acid, nothing is neceflary but to pour 

 W4tei or alcohol over the extra£l. This acid has a pungent 



* From the Anr.ahi cle Chinie, No. 109. 



tafce, 



