406 PRESERVING GRAPES THROUGH THE WINTER 



rature of this month (November) is on the average little 

 above 40°, and the air is generally saturated with moisture. 

 When this is the case, moisture -will be deposited on all 

 substances exposed to the air, if they are not warmer than 

 it is. Grapes that are ripe should therefore be kept 

 warmer than the air, otherwise they will be liable to damp. 

 The application of fire heat would effect this : but if it were 

 applied suddenly, and without air being given at the same 

 time, the heated air would deposit moisture on the berries ; 

 for although these would ultimately acquire the same tem- 

 perature as that of the air surrounding them, yet for a time 

 they would be colder, and so long as this is the case they 

 would act as condensers of the moisture in the warmer air 

 in contact with them. The more rapidly the air is heated, 

 the greater for a time will be the difference between the 

 temperature of the fruit and that of the air, and of course 

 the slower the heating the less at any time will be the 

 difference. Give therefore in damp weather, a little fire 

 heat in the morning and admit air. If the nights are cold, 

 the temperature of the house should not be allowed to fall 

 lower than 45°." 



Here then are nice operations and a lot of trouble to 

 bestow on perhaps half a dozen houses during the winter 

 months ! If the vineries are shaky and badly heated, the 

 task is most difficult and annoying ; in the best constructed 

 ones it is a great and needless labour. The trouble of 

 regulating the atmosphere, the expense for fire heat, and 

 the necessity of keeping the house almost entirely devoted 

 to the grapes, must render any improvement very acceptable. 

 Several times during the spring of 1867 I noticed grapes 

 hanging from branches the ends of which were inserted in 

 vases of water — grapes which the exhibitors described as 

 having been for a long time so preserved in a fresh state. 

 Prom such few specimens I did not derive sufficient confi- 

 dence in the method to speak with certainty of its merits, 

 but having since then visited a good many gardens in which 

 the method is practised, I found that it is accepted as a great 

 boon by some of the best gardeners in France, and their 

 system of keeping grapes has been altered accordingly. 



