GLASS STRUCTURES. 



71 



to carry oft" 



to form a gutter 

 The center planks rest on two 



wide cut out I by 8 inches, 

 water as shown in figure 31. 

 rows of 2x3 inch posts, 

 two and a half feet 

 long and twelve inch- 

 es above the beds: 

 these posts are four 

 feet apart in each row. 

 The total length of the 

 houses here described 

 may vary according to 

 circumstances. The 

 house from which this 

 plan is taken was 100 



fppt lontr Tt was heat- Figure 31.— Valley in market gardeners green- 

 leet long, it was, neat house showing the way tne sasn bar= are at- 



ed with a second hand tached to the plate. 



tubular steam boiler and at an outside temperature of zero, has 

 to carry about five pounds pressure to maintain a temperature 

 of 65 or 70 degrees. Two inch pipes conduct the heat from 

 the boiler, one line of pipe running up each side of the house 

 and both returning through the center at B, back to the boiler. 

 The furnace room is an excavation 10x12 feet and six feet deep, 

 at the northerly end of the house, built with a good wall and 

 roof. The length of pipe required is 450 feet. In the extreme 

 northern states more pipe radiating surface would perhaps be 

 required for best results. The entire cost of material for a 

 structure of these dimensions, boiler and pipes included, 

 amounts to about $150. The cost of steam fitting will have to 

 be added to this, but the rest of the work can be done by any 

 man of ordinary intelligence; Mr. Greiner, whose description 

 has been largely followed in the above, says that he likes the 

 pipes all above ground as here recommended for forcing 

 vegetables, but if wanted for starting seedlings and for gener- 

 al propagating purposes the pipe bad better be placed ten to 

 twelve inches under the surface, and encased in an ordinary 

 three inch drain tile as shown at D figure 30. In sections where 

 fuel is high priced the beds might be partially heated with 

 manure. 



Figure 32 shows a cross section of a lean-to house that is 

 easily adapted to most locations, but especially suited to side- 

 hills. It is twenty feet wide and may be made of any length 



