324 



FRUIT-HOUSES. 



question is one of the common lean-to 

 description. The chamber containing 

 the heating apparatus runs the length of 

 the house, (see /,) and into this chamber, 

 and immediately below the hot-water 



Fig. 435. 





X 





IB * 





i 





Dp 





i 







HI « 













X 



CO 







i 





pipes, are conducted the cold-air drains, 

 both from the back of the house, and 

 also from an air-drain, d, running the 

 length of the house underneath the vine 

 border. The central drain communicates 



Fig. 436. 



with the external air by two drains h h, 

 which are protected by a wire grating. 

 Both sets of drains are furnished with 

 sliding valves made of slate, working 

 in a groove, m n ; to each valve is fixed an 

 upright wooden bar, 

 furnished with holes, 

 and by means of a 

 pin the admission of 

 air can be regulated 

 as wished. In addi- 

 tion to these drains, 

 there are five venti- 

 lators, g, in the back 

 wall of the house. 

 These are made to 

 slide in a frame, and 

 are connected together 

 by an iron rod, having 

 at each end a weight 

 attached, by moving 

 which the whole of the 

 ventilators are acted 

 on simultaneously. 



" It will be seen, by 

 the above description, 

 that when the valves 

 m and n are raised, 

 and the back ventila- 

 tors opened, a current 

 of air is immediately 

 admitted beneath the 

 heating medium, and 

 thus gets warmqd be- 

 fore coming in contact 

 with the foliage of the 

 vines. The general 

 direction of the warmed air is naturally 

 towards the back ventilators. During 

 the winter months, and in dull weather, 

 these valves require only to be slightly 

 raised, keeping a continuous current 

 through the house without lowering the 

 temperature. During bright sunny days 

 I open the whole of them, when, of course, 

 a more rapid circulation takes place ; but 

 I do not find it necessary to open the top 

 sashes until the weather becomes suffici- 

 ently warm that air may be admitted 

 without any fear of its injuring the foli- 

 age by direct exposure to its influence, 

 which often occurs to vines in leaf when 

 the sashes are 

 lowered in cold 

 though bright wea- 

 ther during winter 

 and early spring." 



