THE CULTURE OF THE GRAPE. 139 



temperature of the house, by artificial means, rise above 

 10'^ iu this stage of forcing. 



lu May and June, we often have some very hot days, 

 with a bright sun and dry air, the temperature in the 

 open air 80° or 90°, and even higher ; in such weather, 

 you cannot prevent the heat of the house rising to over 

 100° ; if the air should be very dry, it would burn the 

 leaves, and injure them more to have all the lights and 

 doors thrown wide open, than a greater degree of heat 

 with proportionate moisture would do. 



The shrivel in grapes is caused, frequently, by too 

 large a crop'; sometimes by too much moisture at the 

 roots, and often by a sudden change of air, or too low a 

 temperature ; the best preventive for the two latter 

 troubles is a constant free circulation of warm air.* 



In the management of your house, aim to imitate na- 

 ture, by a regular increase of heat, as in spring. 



Early in October, you may cut back the spurs to two 

 eyes, if you think the wood is not ripening well ; bo 

 careful and do not cut, or otherwise injure, the remain- 

 ing eyes, or their leaves ; this will admit more sun to the 

 house, and promote a free circulation of air, and 

 strengthen the eyes retained. 



In winter, the mercury, in the open air, frequently 

 falls to zero, and sometimes six and ten degrees below, 

 with a high wind blowing at the same time. 



In January, February, and the early part of March, 

 for weeks together, it will be found, during the night, 

 ranging from ten above, down to, zero. In such a cli- 

 mate, a powerful and steady heat is necessary. 

 * See Remarks on Shrivel 



