180 



FORCING-HOUSES. 



to that elevation the position of the sun, in different parts of the year, 

 will be nearly as represented in the annexed sketch, which is taken from 

 the vinery I have mentioned. About the middle of May, the elevation 

 of the sun will nearly correspond with that of the asterisk A, and in the 

 beginning of June, and again early in July, it will be vertical at B ; and 

 at Midsummer it will, at C, be only six degrees from being vertical. The 

 asterisk D points out its position at the equinoxes, and E its position in 

 Midwinter. 



In this building, which is forty feet long, and is heated by a single 

 fire-place, the flue goes entirely round without touching the walls ; and 

 in the front a space of two feet is left between the flue and the wall, in 

 the middle of which space the vines, which are trained to the roofs about 

 eleven inches from the glass, are planted ; and, as both the wall and flue 

 are placed on arches, the vines are enabled to extend their roots in every 

 direction, whilst, in the spring, their growth is greatly excited by the 

 heat which their roots and stems receive from the flue. Air is generally 

 admitted at the ends only, where all the sashes are made to slide to 

 afford a free passage of air through the house, when necessary to prevent 

 the grapes becoming mouldy in damp seasons. About four feet of the 

 upper end of every third light of the roof is made to lift up, (being 

 attached by hinges to the wood-work on the top of the back wall,) to 



