Forcing-House Miscellanies. 



KEMAEKS UPON THE HEATING OF FORCING-HOUSES. 



The only system of heating now in use in large forcing-houses in 

 this country is that of the closed circuit, in which the warming 

 medium is conducted through small wrought-iron pipes, which may 

 be laid either above or below the benches. The warming medium 

 is either steam or water, and there are strong partisans of each. We 

 had never taken sides in the controversy over the comparative 

 merits of the two, for we have believed that each has superlative 

 merits for particular purposes. Various tests which we have made,, 

 however, show that in large, unshaded forcing-houses, where the 

 runs are various and crooked, and especially where high tempera- 

 tures are wanted — as in forcing tomatoes, melons and cucumbers — 

 steam has distinct advantages over water. Our first experiment 

 was made in the winter of 1891-2, and the results were published 

 in Bulletin 41. The general practical results of this test — which 

 was an extended one — were these : 



1. The tem.peratures of steam pipes average higher than those of 

 hot water pipes, under common conditions. 



2. When the risers or flow pipes are overhead, the steam spends 

 relatively more of its heat in the returns, as bottom heat, than the 

 water does. 



3. The heat from steam distributes itself over a great length of 

 pipe more readily than that from hot water ; and steam, therefore, 

 has a distinct advantage for heating long runs. 



4. Steam is preferable to hot water for long and crooked circuits. 



5. Unfavorable conditions can be more* readily overcome -with 

 steam than with water. 



In this first experiment the steam system was more economical of 

 coal than the water system, although we were then convinced that 

 there was no necessary important difference between steam and 

 water in economy of fuel. Objections were made to our conclusions 

 by partisans of water heating, largely upon the score that our water 



