12 



CONSTRUCTION OF VINERY. 



this sheath is one inch more than the hot pipe it en- 

 closes, consequently there is an open space of half an 

 inch all round the pipe inside the sheath. This cavity 

 is fed with fresh air from the exterior of the house 

 by a pipe 5 inches in diameter, which springs from 



Fig. 5. 



HOT-AIR VENTILATOR. 



the low^er surface of the sheath, and passes through 

 the front wall of the house to the external a^r. There 

 is a valve in this feed-pipe to modify the supply of 

 fresh air at pleasure. In the upper surface of the sheath 

 is a double row of small holes, so that the moment the 

 cold air comes into the chamber round the pipe, and 

 gets hot, expanded, and lighter, it makes its exit 

 through these holes into the general atmosphere of the 

 house. In our early vineries the valves are kept open 

 constantly, both night and day, with great advantage 

 to both fruit and foliage. 



CONSTRUCTION OP VINERY. 



As a rule, whether for early or late forcing, I prefer 

 a good-sized house — say, height of back wall, 1 5 feet ; 

 width of house, 1 5 feet ; height of front sashes, 2 feet ; 

 length, 40 feet. A house of these dimensions has a 

 good length of rafter, which enables the vines to carry 



