WINE MAKING. 435 



disastrous effects, which are always shown in 

 weakness of must. These musts will not bear 

 the freedom of treatment that is not only safe, 

 but advantageous to those of better quality. 

 If some restriction is put upon the admission of 

 atmospheric air during fermentation, its violence 

 is abated in some degree, and the danger of the 

 formation of vinegar instead of wine is lessened 

 in the same proportion. Upon this the inven- 

 tion of Mile. Gervais is founded. The bent tube, 

 with its mouth under water, permits the escape 

 of the excess of carbonic acid gas, but at the 

 same time keeps the surface of the wine covered 

 with it, and excludes the atmospheric air. On 

 trial, however, the apparatus was found to have 

 so little practical value, that it has been gene- 

 rally laid aside in Europe. It has been used 

 here pretty extensively in fermenting the must 

 of the Catawba and other grapes, but with what 

 benefit does not appear. 



A more recent question is, whether entirely 

 free or partially closed fermentation is most ad- 

 vantageous for rich musts, and this is now gen- 

 erally settled in favor of the latter, which is 

 usually conducted in pretty large vessels set on 

 end, with a movable outer cover, and an ad- 

 ditional inner cover, as seen in Fig. 174. With- 



