Hot Water Heating. 33 



when they will all be needed, and the saving effected 

 by not having the plants given a check, will oftentimes 

 in one season compensate for the extra expense. 



To lay these pipes, carry one flow nearly to the ex- 

 treme end of your north bench (See Fig. 19), and re- 

 turn it in two pipes laid directly south of it. Put a 

 valve on this flow at some convenient point near where 

 it enters the house, and these three pipes can be used 

 at will. Carry another flow under the south side of the 

 same bench to within one foot of the extreme end, put 

 on an ell and carry across the end of the house, bring- 

 the water back under the south bench in four pipes, 

 and when these approach the boiler they may be 

 united in one and returned to it in that form. 



In this way you have your heat on the outside of 

 your house for the entire distance, leaving the space 

 under the middle bench clear and free. I have noticed 

 that if the circulation is carried up and down a house 

 without crossing the end farthest from the boiler, sev- 

 eral feet of that end will be cooler than any other part 

 of the house, causing dampness to be driven there, and 

 a consequent condensation of moisture on the foliage 

 during the night, which will soon cause the leaves to 

 fall. 



The inlets to a boiler should always be greater than 

 the outlet, and it is customary to use them in the pro- 

 portion of a four-inch outlet or flow to two inlets or re- 

 turns of the same size. If the boiler is of suitable ca- 



