EFFECT OF OAK-CASKS UPON WINES. 183 



Butyric JEther. — This ether is used for imitating rum, on ac- 

 count of its agreeable apple-odor. To obtain it dissolved in 

 alcoholjWohler recommends (Pogg. Ann. xlix. 360) saponifying 

 butter with strong potassa-lye, dissolving this soap in the least 

 amount of alcohol, by the aid of heat, adding to it a mixture 

 of alcohol and sulphuric acid until it has a strong acid reac- 

 tion, and distilling it as long as the distillate possesses the 

 apple-odor. 



Sulphuric Acid in Wines. — Lassaigne (Ann. de Ch. et de 

 Phys. xxi. 119) proposes a very simple and delicate test of the 

 presence of sulphuric acid in wines. When a piece of white- 

 glazed paper, containing starch, is touched with pure wine and 

 dried at a gentle heat, no spot is produced ; but if sulphuric 

 acid be present, even to the extent of yuuu> the spotted portion 

 reddens and becomes brittle between the fingers before the 

 white paper becomes at all colored. Pure wine leaves, by 

 spontaneous evaporation, a violet-blue spot, but if containing 

 2-3 thousandths of sulphuric acid, a rose-red spot. 



Effect of OaJc-casJcs upon Wines. — Fame (Journ. de Pharm. 

 et de Chim. xiii. and Millon and Reiset's Annuaire, 1849) 

 gives the following conclusions, based upon the results of a 

 series of analyses. 



1. That the oak woods used by the coopers for making wine 

 and liquor casks are the same ' in composition ; though the 

 proportions of the ingredients vary with the place of growth 

 of the tree. 



2. That the soluble principles of oak-wood have an appre- 

 ciable action upon liquors, and particularly upon wines. 



3. That this action is more evident upon white than upon 

 red wines ; more so upon light and delicate than upon colored 

 and coarse wines. 



4. That American oak contains less soluble matter than other 

 kinds. 



5. That casks made of American, Dantzic, or Stettin oak, 

 have, in general, the least action upon spirituous liquors. The 

 two latter even, sometimes, improve the quality of the wines. 



G. That alkalies increase the color and solubility of the ex- 



