68 



GARDEN FARMING 



TABLE I. RELATION OF GLASS SURFACE, RADIATING SURFACE, AND 

 HEATING SURFACE l 



The figures in the columns headed Hot-water Heating and Steam Heating 

 in Table I indicate the number of square feet of surface exposure that can be 

 supplied by i foot of radiation when the hot water or steam in the radiating 

 pipes is at the temperature indicated at the top of the column, and when the 

 temperature desired in the house is indicated in the left-hand column of Table I. 



Size of pipes connecting radiating surface and boiler or heater. 



Various writers have given empirical rules for proportioning main- 

 supply and return . pipes, which have proved quite satisfactory in 

 practice. The following by George Babcock will be found satis- 

 factory for greenhouse heating, whether with low-pressure steam 

 or with water : 



The diameter of the main pipe leading to the radiating surface 

 should be equal in inches to o. i of the square root of radiating sur- 

 face in square feet. No main pipe should be less than 1 1 inches 

 in diameter. For water heating return pipes should be the same 

 size as main pipes, and for steam heating merely large enough 

 to return the water which was converted into steam. In practice 



1 Rearranged from Carpenter's work "Warming by Hot Water and Steam." 



