. 



290 GRAPE CULTURE AND 



objectionable, is one of the most common and prominent 

 causes of unsoundness, and should Ue done away with uni- 

 versally, adopting either the use of floating covers, or at least 

 a cover over the top of the tank. Whether the disadvantages 

 of the single-frame system can be overcome by a repeated 

 pumping over of the liquid from below over the pomace, is a 

 question yet to be determined; but that in the use of this 

 method there is always a serious loss of color and tannin cart 

 hardly be doubtful. 



E. W. HILGARD. 



CHAPTER V. 

 D'HEUREUSE AIR TREATMENT. 



Alleged improvements, involving sweeping changes in many 

 industries, should above all bear the light which close practical 

 investigation may shed upon errors to which new as well as 

 time-venerated doctrines are subject; corroborative tests only 

 can establish their value. Theories, apparently sound, by 

 neglect of some essential condition, may fail to be confirmed 

 by tests. One of the most general and firmly rooted notions 

 has been the dread of access of air during fermenting or pre- 

 serving operations; the most satisfactory proofs only will es- 

 tablish the fact that exclusion of air should be abolished, and 

 that the suggestion of air-treatment as a safe, cheap, easy and 

 effectual agent for wine and other industries is well founded. 

 For the sake of our American wine industry it is proposed to 

 review the principles on which air-treatment is based, the 

 manipulations, the advantages claimed, and the conditions to 



