DETACHED GREENHOUSES, ETC. 169 



south, so that the distribution of light will be equal on 

 each side : the east side in the morning and the west in 

 the afternoon. 



All the walling from the surface of the ground to the 

 glass of a greenhouse had better be made of wood, unless 

 the walls are made very thick when built of brick or 

 stone. The continued warfare in winter between a zero 

 temperature outside and sixty to seventy degrees inside, 

 will in a few years destroy brick or stone walls. When 

 the walls are formed of wood, the best way is to place 

 locust posts at distances of four feet apart, and nail to 

 these a sheathing of boards. Against the boards tack 

 asphaltum or tarred paper, and again against that place 

 the weather-boarding. This forms a wall which, if kept 

 painted, will last for fifty years, and is equally warm as 

 a twelve-inch brick wall, and costs less than half. A 

 common error is to board on each side of the post and 

 fill in with sawdust or shavings. This should never be 

 done, as this filling soon decays, besides forming a resort 

 for mice and other vermin. We have had just such a 

 structure (as figure 57) in use fifteen years as a cold 

 grapery, that has no heating apparatus, the forwarding 

 being done only by the action of the sun on the glass, 

 and it has proved a cheap and satisfactory luxury. A con- 

 servatory or grapery of this style (figures 56 and 57) costs 

 from fifty to sixty cents per square foot, without heating 

 apparatus. Heated by hot water, it would cost one dol- 

 lar to one dollar and twenty-five cents per square foot. If 

 heated by a horizontal flue in the manner here described, 

 the cost would be about seventy-five cents per square foot. 



GLASS AND GLAZING. 



If for winter forcing of either fruit or flowers, the 

 glass should be not less than ten by twelve in size, 

 laid in the twelve way, and if twelve by twenty all the 

 better. Even with the greatest care, some flaws in 



