GLASS STRUCTURES. 



67 



The heat from a flue is very dry, and much more water is 

 required when hotbeds are heated in this way than when manure 

 is used as the source of heat. 



A Greenhouse Hotbed. A greenhouse may be heated by 

 manure or a combination of manure and some other way of 

 heating-. In the following- lines and illustrations is given the 

 plan of what may be called a greenhouse hotbed which has 

 been in very successful operation at the Minnesota Agricultural 

 School. The description is from an article on the subject by 

 R. S. Mackintosh, of the Division of Horticulture. 



"There are disadvantages in hotbeds, as, for instance, the 

 transplanting, ventilating-, watering, etc., must be done from the 

 outside even in severe weather, while in a house like the one 



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Figure 27.— Plan and elevation of hotbed greenhouse. 



shown in the figure these operations can be carried on easily. 

 The house is simply a hotbed built so as to allow a person 

 to g-o inside to do all the work of caring for the plants. 

 Figure 27 shows the general plan of the house. The size is 



