98 PRACTICAL FLORICULTURE. 



wooden wall of a greenhouse hollow, filling up the space 

 with sawdust, or some such non-conducting material. 

 The method found best is to sink locust, cedar, or chest- 

 nut posts to the required depth, and at distances of four 

 or six feet apart ; against these (outside) nail common 

 rough boards ; then against these tack asphalt or tarred 

 paper, and against that nail the ordinary weather board- 

 ing. Such a wall will resist cold better than an eight- 

 inch brick wall, and will last for twenty years, if kept 

 painted. If a better finish is desired inside, the posts can 

 be hid by weather boarding ; but nothing should be put 

 in to fill the space. When the walls have been finished 

 to the required height, the wall plate to secure the rafters 

 is laid on. Supporting posts should be placed under the 

 ridge-pole, and also near the middle of the rafters, where 

 these are very long, as is the case in many of the three- 

 quarter span houses. At present prices, the cost of a 

 Rose House, as shown in figure 24, is about $15 per run- 

 ning foot, heated by hot water or steam, complete, or 

 $1,500. 



CHAPTER XVIII. 

 GLASS, GLAZING AND SHADING. 



If for winter forcing of either fruit or flowers, the 

 glass should (as we have before said) be not less than ten 

 by twelve inches in size, and laid in the twelve-inch way. 

 It should be of what is known as second quality French, 

 and it is economy always to use the double thick. All 

 panes should be rejected having flaws or " blebs," as these 

 will act like lenses, and, forming a focus for the sun's 

 rays, will burn the leaves of the plants ; but even with the 

 greatest care, some flaws will usually remain, and less or 



