32 



the walls may be built upon chestnut posts set deep in the ground, 

 or cast-iron posts made for this purpose. The north wall is made 

 of non-conducting material, while the south wall is of glass. 



The even span house (Fig. 3) is generally placed north and 

 south, and has the advantage of exposing the plants to sunlight 

 upon all sides, and receiving the greatest amount of sun's heat and 

 light in the morning and afternoon. This is much used for the 

 growth of roses, chrysanthemums, etc. 



The side hill house (Fig. 4) possesses some advantages over 

 those already mentioned. When built on a south, south-east or 

 Bouth-west slope they are perfectly protected on the north, and 

 susceptible of perfect drainage, no matter what the nature of the 

 soil. The cost of the side walls and the terrace walls (Fig. 4, a) 

 is much less than that of outside walls and beds or benches in the 

 other forms of houses. It is practically a o?re-roofed house with no 

 gutters. One objection to this form may be found in the effort 

 required in going up and down from one part of the house to the 

 other. 



Materials. 



The best wood for greenhouses is cypress or clear heart white 

 pine, the former being generally considered the best because of its 

 straight grain and the great length, but it is more liable to warp 

 out of place unless firmly nailed when put in place. 



Foundation. 



A good foundation must be provided or a house will often settle 

 out of shape, and such light structures are easily ruined by this 

 settling. Stone, concrete, brick, iron and wood may be used for 

 foundations. Stone foundations should be put in below the reach 

 of frost, and be well laid in mortar containing one-fifth Portland 

 cement. Concrete can be made by digging a trench from eight 

 inches to one foot wide and tamping in a rather dry mixture of 

 Portland cement, one part to five of sand and small stone. The 

 parts above the surface must be held in place by planks and be put 

 in moist enough to be poured in from a pail. When nearly set a 

 skim coat of cement and sand, one to three parts, may be added, 

 used to dress up the surface. If good cement is used and is prop- 

 erly mixed a permanent and neat foundation wall can be made. 



Stone foundations are more generally used with brick to top 

 them out with, but to be satisfactory the brick must be laid in 

 cement mortar. Many good houses are built by sinking chestnut 

 or cedar posts three and one-half or four feet below the surface 

 and standing above the surface high enough to form the walls 

 upon. The north walls of the three-quarter span house may be 



