404 ANNUAL KECOKD OF SCIENCE AND INDUSTRY. 



whicli take place between the mineral substances, organic salts^ 

 and the ali3uminoid and colloid substances of the wine, the 

 small quantity of acid added is rendered fixed and insoluble. 

 These results, in the opinion of the writer, confirm the ex- 

 periments of Professor Chancel, who has ascertained that 

 whenever the must is alkaline, the sugar, instead of being 

 transformed into alcohol, is converted into lactic acid, from 

 which wine, of course, can not be produced. The addition of 

 the acid, however, counteracts the alkalinity of the must, and 

 places the grape sugar in the conditions necessary to produce 

 alcohol. In some instances, the precise source of the alkalin- 

 ity referred to, although a serious matter, is not clearly under- 

 stood ; but Dr. De Martin suggests that it is j)ossibly caused 

 by the grapes becoming covered with mud in consequence of 

 rain, which is thus accumulated in suflicient quantity to give 

 an alkaline reaction to the liquid, resulting in a poor fermen- 

 tation. 9 B, June 2, 1872,506 



PEESERVATIOJ!^ OF W INE BY HEAT. 



In a memoir upon the employment of an elevated temper- 

 ature for the improvement and preservation of wines, Verg- 

 nette-Lamotte gives the following conclusions as the result 

 of his experiments : 



1. If we heat new wines, rich in soluble matters, we give 

 them the character of the wines of Spain and Portugal. 



2. In the application of heat, we must take into considera- 

 tion the amount of alcohol contained in the wine, its vinosity 

 (proportion of alcohol) permitting us to lower the degree of 

 heat needful for its improvement and conservation. 



3. The age of a wine has a very great influence upon the 

 character which it presents after heating. This process does 

 not succeed with old wines. 



4. It is equally needful to take account of the time the wine 

 has been in the wood and in bottle. 



5. Heating gives, in general, excellent results with white 

 wines. In applying it to new wines, still rich in soluble mat- 

 ters, we preserve in them that precious quality technically 

 known as " liqueur." 



6. The degree of heat is a capital point ; that suitable for su- 

 perior kinds of Burgundy, rich in alcohol, is 112 Fahr. There 

 exist, in fact, for each wine, peculiar conditions of heating. 



