FRUITS AND PLANTS 151 



advantage. In his experiments Professor Sanderson 

 used small paper covers, pyramidal in shape, the apex 

 being eight inches high and fastened to the inside of a 

 wooden frame three inches high by twenty inches 

 square. The lower edge of the frame was beveled on 

 the lower edge and could be easily pressed into the 

 soil. A good quality of building paper, cut in one 

 piece, can be used as covers. The cost of the covers 

 complete should not exceed four cents each. 



After making over seventy-five tests Professor 

 Sanderson is of the opinion that about four- tenth (0.4) 

 gramme cyanide per cubic foot exposed ten minutes 

 is sufficient. In some tests young cantaloupes, fumi- 

 gated immediately after a shower, were somewhat 

 injured. The plants should be as dry as possible and 

 the amount of cyanide reduced to three-tenths (0.3) 

 gramme per cubic foot in some cases. The seemingly 

 large amount of gas used on these low-growing plants 

 is due to the fact that a larger proportion is lost in the 

 small covers than in a large enclosure. Where plants 

 are 5x5 feet apart, the cost of fumigation per acre, 

 even at the maximum amount, is about seventy-five 

 cents for chemicals. Two men with one hundred 

 covers should fumigate from three to five acres per 

 day, depending somewhat on conditions. 



Plants in rows. The fumigation of plants in rows 

 is rather difficult and expensive. To compensate for 

 the influence of soil and foliage, a larger amount of 

 gas per cubic foot of space must be used to accomplish 

 the same results than in a box or other enclosure. 

 Prof. C. L. Penny, chemist at the Delaware Experi- 

 ment Station, has shown conclusively by analyses that 



