CULTIVATION OF THE GRAPE UNDBE GLASS. 145 



a Eepresents the flow pipe running along the front of the 

 vinery, and if there he several, the one nearest to the front wall; 

 5 is a tin or galvanized iron covering, made to enclose the hot 

 water pipe, hut having a diameter one inch more than the hot 

 pipe it encloses, and hrought down at the ends so as to fit tight 

 at those points, thus enclosing a space of half an inch aU round 

 the flow pipe inside the sheath. This cavity is fed with fresh 

 air from the exterior of the house hy a pipe, c, five inches in 

 diameter, which springs from the lower surface of the sheath, and 

 passes through the front wall of the house to the external air. 

 There is a valve, d, in the 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 m6ment the cold air comes into 

 the hot 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 this way a constant supply of fresh 

 air can be obtained without causing a cold draught. This is 

 more especially desired for houses used for early forcing, at which 

 season the weather is nearly aU the time so cold that it is unsafe 

 to open the front ventilators. 



It is always desirable to have some means of heating even a 

 cold grapery, for it often happens that the warm days of early 

 spring, which start the vines nicely, are followed by a period of 

 chilly weather, accompanied by frosty nights, and unless the 

 temperature of the house can be kept up the vines become severely 

 chilled, and sometimes in a single night they will receive a shock 

 from which they will not recover in a fortnight. For this pur- 

 pose, however, a couple of pipes, running around the house, will 

 be quite sufficient, and can be used at such times, either in the 

 early spring, or when in bloom, or in the damp weather in the 

 fall. 



The best boiler, aU things considered, for a small house, is the 

 plain saddle boiler. It is quite unnecessary to enter upon a 

 discussion here of the merits of the many boilers which have 

 been invented, and aU of which are advertised as "improved." 



