PINERIES. 



343 



the surface covered with a few inches in 

 thickness of rotten dung or leaves, which 

 will not only resist the cold during 

 winter, but will also tend to keep the 

 roots of the vines dry. 



Span-roofed pinery. — Fig. 462 shows 

 the section of a span-roofed pinery, the 



Fig. 462. 



ends being placed north and south. To 

 be under the command of one fire, it 

 may be 35 feet in length and 17 feet 

 wide within, and 8 feet from the floor to 

 the ridge. With two fires, one at each 

 end, it may be double this size, or 70 feet 

 long. Heat is applied by the tanks 

 a a a a, hot-water pipes b b, and smoke- 

 flue c under the passage. Ventilation is 

 obtained by introducing cold air through 

 the side walls, and close to the ground- 

 level, through earthenware tubes d d, 

 3 inches in diameter, and 3 feet apart. 

 These tubes have an opening equal to 

 half their diameter on their upper sides 

 at e, to allow a portion of the air to 

 ascend in the space between the walls 

 and tanks, and disperse itself into the 

 house under the hot-water pipes. The 

 air-tubes also pass under the tanks, and 

 terminate flush with the walls of the 

 tanks and level with the floor, their ori- 

 fices being furnished with a revolving 

 brass ventilator to regulate the admission 

 of air from without. The openings at 

 the external ends, being in a line close to 

 and parallel with the side walls, are opened 

 and shut more or less by metallic stoppers 

 attached to the lower side of an iron bar 

 extending the whole length of the house, 

 and placed immediately over the open- 

 ings, and elevated or lowered by means 

 of a rack and pinion attached to it at the 

 middle, by which all can be opened or 

 shut at once. The cold air admitted 

 through these tubes becomes genially 

 heated before it comes in contact with 



the plants— a very important feature in 

 all kinds of ventilation. Top ventilation 

 is accomplished by an opening in the 

 ridge 8 inches wide, and extending the 

 whole length of the house. There are 

 various ways of opening and shutting 

 this part of the ventilation — (vide section 

 Ventilation.) In the house in question 

 it is shown upon a simple principle — 

 namely, an iron rod extends along the 

 ridge, which is open, as 

 shown above. To this rod 

 is fixed a board 8 inches in 

 breadth, which, as the iron 

 rod or axle is turned by a 

 handle at one of the ends, 

 revolves with it ; — and when 

 the full ventilation is on, it 

 stands perpendicular; when 

 half on, obliquely; and when 

 entirely shut, quite flat. To prevent the 

 rain from entering, a fixed coping is placed 

 a little above the opening of the ridge, of 

 a semicircular or angular form, either of 

 wood or cast or wrought iron, leaving a 

 space of 6 inches clear along both sides of 

 the ridge ; or it may be covered close at 

 top, the openings of the sides being opened 

 and shut upon the Venetian principle. 



The heated air and smoke, after pass- 

 ing the boiler, are carried along the flue 

 c, placed in an air-chamber imder the 

 passage. A ventilator, graduated by a 

 revolving plate 12 inches in diameter, 

 and opening to nearly half that size, is 

 placed at the end of the air-chamber 

 nearest to where the flue enters it, through 

 which a current of atmospheric air enters, 

 and, passing along above and by the 

 sides of the flue, becomes moderately 

 heated, and is admitted into the house 

 through gratings placed in the floor for 

 the purpose. 



The pipes extend the whole length of 

 the house, and return by the same route 

 to the boiler. The tanks are of brick and 

 cement, covered with pavement ; over 

 this is the drainage // on which the pots 

 are set, or bed formed if the plants are to 

 be planted out. The passage is 3 feet 

 wide, the beds 7 feet each, including the 

 hot-water pipes, and a clear space of not 

 less than 2 or 3 inches is left between the 

 pipes and the wall. 



Of all forms the span roof is best 

 adapted for the culture of the pine, as 

 every part of the plant requires the full- 



