Journal of AgricuLture. [lo Nov., 1909. 



oil to dilute it to the consistency of ordinary house paint. It may then 

 be brushed on to the parts affected. This mixture will keep ; and should 

 it thicken it may again be reduced by the addition of more linseed oil. 

 This is a very effective paint, and is easily handled where the attacks ot 

 Woolly Aphis are too light to warrant the use of the spray pump. 



SHERRY: ITS MAKING AND REARING. 



/•'. de Castclla, Government Yiticidtiirist. 



{Concluded from -page 630.) 



\atural Increase in Strength. 



That the alcoholic strength of sherry increases on storage in the 

 bodegas, has already been pointed out (page 519). Though I was con- 

 vinced of the accuracy of the statements made to me concerning it, in Jerez, 

 it is so little in accordance with usual cellar experience that I was glad 

 of an opportunity, on my return to France, of discussing the subject with 

 Professor Bouft'ard, of the Montpellier School. He w-as able to fully 

 corroborate what I had been told in Jerez, and mentioned similar cases 

 which had come under his notice in France, especially in parts of the; 

 Roussillon district, where the natural strength of some of the wines made 

 is high. He knew of special wines, kept in cask for years, in lofts of 

 farm houses, where the natural increase in strength had been considerable. 

 The conditions under which such increase occurred are very different to 

 those prevailing in cool underground cellars, but similar to those met with 

 in the well ventilated, aboveground bodegas of Jerez. The factors 

 responsible for such changes, and the physical laws which govern them, are 

 extremely complex, nor do they appear tO' have been experimentally investi- 

 gated. They are, no doubt, intimately connected with the tensions of 

 alcohol and water vapours, given off by mixtures of these liquids, in dif- 

 ferent proportions under different conditions of temperature, pressure, ullage 

 of the cask, dryness of the air, &c., each of which exerts its influence, ap 

 does also the wood of which the cask is made. It has long been known 

 that spirits kept in bladders increase very considerably in strength, water 

 passing through the membrane and evajwrating at its surface more readily 

 than alcohol. The wood of the r;isk appears to act in like manner, and it 

 is to this action that the increase is, in all probability, mainly due. 

 It is, of course, only relative, there being no real gain in the absolute 

 quantify of alcohol present, as would occur were the phenomenon due 

 to fermentation. A portion of the alcohol evaporates also, but its loss 

 being much slower than that of water, a relative gain, or, in other words 

 an increase in strength is observed. 



Tills development is better known in spirit stores tlian in wine cellars. 

 In the cool and often moist atmosphere of the latter, conditions are 

 entirely different, the loss of water being considerablv retarded, so much 

 so that, instead of an increase, a slight diminution of strength mav result. 

 In fact, this is usually w-hat is noticed in a cool, well-kept wine cellar., 

 A similar increa.se has often been obser\ed in the case of brandy and other) 

 alcoholic liquors stored in bond and ai'ciiratclv gauged at regular intervals 



