324 



Journal of Agricultural Research 



Vol. XII, No. 6 



external surface of each container was exposed to any temperature 

 change. These changes were further minimized by surrounding the set 

 of containers with a boxing, i8 inches high, placed 6 inches from the 

 outside of the entire group. This 6-inch space was then filled compactly 

 with local soil. The insulation furnished by this arrangement was excel- 



/&-&■ 



/©•-6" 



Fig. 2. — Diagram of the arrangement of the soil containers. 



lent. No difference in growth was observed in any portion of the con- 

 tainers. 



Protection from birds was assured by a framework, 4^ feet in height 

 above the containers, covered with i -inch-mesh wire netting. The general 

 arrangement of the two sets is shown in Plate 14, A. 



