VARIOUS METHODS OF HEATING DESCRIBED IN DETAIL. 205 

 Fig. 42. 



departments are heated by one boiler ; some of them going at 

 one time, and some at another, and sometimes all going together, 

 and each having abundance of heat.^ The convenience of this 

 system cannot be too highly appreciated, especially when there 

 are a number of small plant-houses situated near each other. 

 For instance, suppose the boiler to be at work for one of the 

 houses, which may be a plant-stove or forcing-house ; well, you 



Fig. B. 



* Fig. B shows the common method of placing supply-cisterns. They 

 may be placed in some convenient situation and attached by a small 

 pipe to the apparatus. To prevent the escape of vapor, it is desirable 

 to bend the pipe into the form shown at a b, as the water in the part of 

 the inverted syphon at a, will remain quite cold. 



