144 CULTIVATION OF THE GRAPE UNDER GLASS. 



Fig. 47 represents the ground plan of a vinery, showing the 

 "water-pipes and boiler. The hot water flows from the top of 

 the boiler, runs through the pipes along the front and ends, 

 and returns to the bottom of -the boiler by the two pipes along 

 the back of the vinery 



K a span-roofed house is preferred, the construction will be 

 much the same as that already described. Of course there will 

 be no back wall, but in place of it, another roofing of glass ; and 

 instead of the top ventUators being as in the " lean-to," there 

 must be some arrangement made at the ridge of the roof. A 

 convenient arrangement is to run the astragals to the ridge on the 

 west side, and glaze that side tight to the top. On the east side, 

 TUB the astragals only to >vithin about eighteen inches of the top, 

 and between every other rafter place a ventilator, three feet long 

 and one foot wide, hinged on the upper edge, and rabbeted so as to 

 lap over half an inch on the lower side and at the two ends, when 

 closed. On the inside, near the lower edge, is fastened, with 

 a staple, a small rod, with which the ventilator can be pushed 

 open and kept at any desired elevation. 



Or, instead of ventilators fastened on hinges, narrow sashes 

 may be made to slide down and up between the rafters, which 

 are opened and shut by a cord passing over pulleys. The only 

 objection to this latter method is, that sometimes, in freezing 

 weather, the sliding sash becomes frozen fast, so that it cannot 

 be made to slide; though, with proper attention, it will very 

 seldom be necessary to open the top ventilators in such weather. 



Fig. 48. 



The above diagram illustrates the method of admitting 

 fesh air into the vinery in cold weather, when it is impossible 

 to open the side or front ventilators with safety. 



