THE CULTURE OF THE GRAPE. 107 



best preventive for the two latter troubles is a constant free 

 circulation of warm air.* 



In the management of your house, aim to imitate nature, 

 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 ayoocI is not ripening well ; be careful and do 

 not cut, or otherwise injure, the remaining 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 below, with a liigh wind blow- 

 ing 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 climate, a powerful 

 and steady heat is necessary. 



The boiler and pipe to circulate hot water around the 

 house, on the level principle, together with the furnace and 

 flue, are recommended as the best and safest heating appara- 

 tus. A furnace and flue will not heat more than twenty-five 

 feet of a grapery that is forced in the winter months, and, for 

 any additional length of the house, other furnaces must be 

 added, in the like proportion, or the hot water apparatus sub- 

 stituted.! 



The followmg is a memorandum of the regulation of the 

 heat, with the dates on which the different operations were 

 performed, in a house forced in the winter of 1846 and 

 1847 :— 



November, 1846. — The vines were pruned ; every alternate 

 spur was cut at one eye to fruit ; the others were cut close, 

 as there were more spurs than the strength of the vine w^ould 

 admit of fruiting the coming season. 



When the vines were not of sufficient length for the rafters, 



* See Remarks on Shrivel. 



t Polmaise System, and the manner of building ihe furnace, are described luider 

 the head of Furnaces, &c. 



