78 PRACTICAL FLORICULTURE. 



ing's Combination Boilers (0), heating about 1,200 feet 

 of four-inch pipe (D). The glass roof (E ) is formed of 

 portable sashes, each six feet by three feet ; each alter- 

 nat3 sash is screwed down, the others being movable, so 

 that a full supply of air can be given when necessary. 



The movable sash is elevated by an iron bar fifteen 

 inches long, attached to the sash by a staple ; in this bar 

 three holes are punched, at distances of three inches 

 apart ; by means of these holes the bar can be hooked 

 upon an iron pin placed in the ridge-pole, and thus 

 hold the sash more or less open, to graduate the admis- 

 sion of air. When the sash is shut down, the bar is 

 hooked on to a pin that secures it in place, so that the 

 sash cannot be moved by wind. I am particular to 

 describe this method of airing, as it is, as far as our expe- 

 rience has gone, the best method we have ever seen used. 

 The ridge-poles are cut out exactly as is shown at J, and 

 the sash lays on the shoulder, braced by the angle shown 

 in the cut. The interior arrangements are shown by the 

 end section. G shows the bench, or table, as it is com- 

 pleted. The space beneath the bench, if bottom heat is 

 required for propagating or other purposes, should be 

 boarded up below the bottom of the pipes, the lower board 

 being hinged, so that, on cold nights, additional heat can 

 be given to the atmosphere of the house, if required. But 

 for the general uses of growing plants, the benches must 

 be left open below, so that the heat given out by the 

 pipes will pass freely to all parts of the house. If one 

 house is wanted of a higher temperature than the others, 

 it will be necesary to board up along the posts from the 

 ground to the top of the posts, and by wholly or partially 

 shutting the valves in the pipes of the other houses, 

 throw a greater heat into the one in which the high tem- 

 perature is wanted. The walks through the house (K) 

 are two feet wide, which leaves four feet and one-half on 

 each side for bench room. Thcss widths we find to be 



