VARIOUS FORCING METHODS. 83 



covered with five or six inclies of horse manure. Tliis 

 covering was to prevent tlie heat from escaping from 

 the soil too rapidly. It was then ready for the steam 

 to be turned into the tunnels. In the illustration one 

 of tlie tunnels has been uncovered to show its construc- 

 tion. 



To conduct the steam a one and one half inch pipe 

 was carried above ground from the boiler to one end 

 of the central tunnel, a distance of 185 feet. A steam 

 liose long enough to reach eacli tmmel was attached 

 to this pipe through which lo blow steam into the 

 tunnels. It was not the idea to give a constant supply 

 of steam, but to discharge a little into the tunnels each 

 afternoon, or a^ often as was necessary to maintain 

 sufficient Avarmth. A piece of tile was inserted into the 

 mouth of each tunnel to prevent the discharging steam 

 from tearing away the earth. 



The first steam was turned into the tunnels on 

 Xovember 14. Steam was discharged into each tunnel, 

 not to exceed five minutes at a time, in order not to heat 

 the earth too hot in any single place. It required about 

 one liour of steaming the first day to bring the bed u]) 

 to the required temperature of GO degrees. The dis- 

 tribution of heat througliout the bed was very uniform 

 and satisfactory. The moist steam seemed to permeate 

 the soil equally in all directions. 



After the first day, very little steaming was neces- 

 sary until the crop Ijcgan to be produced. On an average 

 the bed was steamed al^out twice in three days and then 

 onlv for al)out five jninutes for each tunnel. The soil 

 and horse manure mulch seemed to hold the heat very 

 well, the frequent steamings keeping up fermentation 

 in the mulcli. 



The first picking was made in ten days. When steam 

 was not turned on until tlie last of December, the crop 

 was not ready until the middle of January. Tlie results 

 are thus summarized by Horticulturist Whitten : — 



The steam, comino- in direct contact with the soil, 



