350 



Glass 



the quantity of manure. Hotbeds that are supposed to 

 hold two months should have about two and one-half feet 

 of manure, as a rule. This is the maximum. For a light 

 hotbed to be used late in the season, six or eight inches 

 may be sufficient. 



Various modifications of the common type of hotbed 

 will suggest themselves. If the hotbed were high enough 

 and broad enough to allow a man. to work inside, we 



would have a 

 forcing house. 

 Such a structure 

 is shown in Fig. 

 217, upon one 

 side of which the 

 manure and soil 

 are already in 



217. Manure-heated toroing-tiouse. plaCC. TwO to 



three feet of manure should be used. The house may be 

 covered with hotbed sash held on a rude frame of scant- 

 lings. These manure-heated houses are often very efficient, 

 and are a good make-shift until such time as one can afford 

 to put in flue or pipe heat. 



Pipe-heated liotieds. 



Hotbeds may be heated by means of steam or hot water. 

 They can be piped from the heater in a dwelling-house or 

 greenhouse. Exhaust steam from a factory can often be 

 used with very good results. Fig. 218 shows a hotbed 

 with two pipes, in the positions 7, 7, below the bed. The 

 soil is shown at 4. Doors in the end of the house, shown 

 at 2, 2, may be used for ventilation or for admitting air 



