February, '10] hinds and turner : carbon di-sulfid 53 



So far as Calandra was concerned, the results from a treatment at 

 the rate of 3 pounds for 24 hours was the same as with 4 pounds for 16 

 hours, 83 per cent being killed in each case. In some experiments, 5 

 pounds was completely effective in 15 hours, while in others only 95 

 per cent were killed in 20 hours, and the difference seems due entirely 

 to the difference in temperature. Seven and one half pounds at 47 

 degrees killed 93 per cent in 4 hours and 100 per cent in 24 hours at 

 60 degrees. Ten pounds was completely effective in 24 hours for all 

 wee\dls at 60 degrees, as was also 12% pounds in 20 hours and in 16 

 hours at the same temperature. Fifteen pounds was completely effec- 

 tive in 16 hours at 52 degrees, as wals also 20 pounds in 5 hours at 60 

 degrees. Further experiments are being made to determine these 

 limits. 



Taking up next the work done on a larger scale, we may mention 

 ■two series of experiments performed at Montgomery, Ala., during the 

 past fall. At one place, some 2,500 to 3,000 bushels of corn were 

 stored in two exceptionally tight buildings constructed for that pur- 

 pose. The walls and floors of these buildings are of cement and are 

 built solidly to a height of about nine feet above the ground, with the 

 floors slightly lower. Wooden partitions made of flooring divided 

 the buildings into several rooms. The partitions were not at all tight, 

 but the walls up to the eaves were unusually so. Com was stored in 

 several of these rooms about the first of September. It then contained 

 many weevils, as the infestation during the present season is unusu- 

 ally severe. About two weeks after this corn was stored, the owner 

 applied 20 pounds of commercial bi-sulfid, using about 10 pounds of 

 it in the largest of the cribs, which contained approximately 2,000 

 cubic feet. The single door was closed, but not so as to fit tightly, 

 and large cracks existed between the roof and the wall at the eaves. 

 This room, therefore, received an application of about 5 pounds per 

 1,000 cubic feet, and the prevailing air temperature in the vicinity at 

 this time was about 80 degrees (70-91 degrees) for three days. The 

 smaller bins received from 2% to 3 pounds per 1,000 cubic feet. 

 Examinations of this corn were made about three weeks after the 

 treatment and showed considerable numbers of living weevils, espe- 

 cially near the doors. It appeared that there was still sufficient 

 infestation to warrant further treatment under such unusually tight 

 crib conditions. Even at that time it was evident that the treat- 

 ment in the larger bin with 5 pounds per 1,000 cubic feet had been 

 quite fairly effective and more so than were the other treatments in 

 the smaller bins. 



In preparation for the second treatment, a thorough examination 



