cloudy days, and probably the length of time during which it could 

 act on the scales was thereby somewhat reduced, though no percep- 

 tible difference in the results on this account was found. 



Method of Determining Results. 



It has been customary to judge of the results of any treatment by 

 examining the trees three or four weeks afterwards, and determining 

 the percentage of living scales found. This method is defective 

 however, as many scales normally die during the winter months and 

 any such examination would fail to show the number really killed by 

 the treatment. The method adopted, therefore, was to inspect the 

 trees as soon as the first crawling young appeared (June 23d), and 

 to reinspect every week or two during the summer and fall. In this 

 way the abundance of young on a tree was an indication as to the 

 success of the treatment. 



The Treatments and their Results. 



The methods used naturally fall into three groups : i. Treatment 

 by fumigation ; 2. Treatment with standard materials; 3. Treat- 

 ment with materials sent for trial by the manufacturers. These 

 groups will now be considered in detail. • 



I. Fumigation. 



For fumigation a canvas box tent was used, made according to the 

 plans given in Bulletin 181 of the N. Y. Agricultural Experiment 

 Station. The tent was made by stretching canvas over alight frame, 

 the canvas having been painted with dark paint until it was air-tight. 

 One side was removable and when in place shut against felt and was. 

 secured by bevelled buttons. The tent complete was ten feet high, 

 six feet in diameter and cost $20.00. Twenty-five hundredths of a 

 gram of Potassic cyanide, 99% pure, was used for each cubic foot of 

 space within the tent, with one and a half times as much commercial 

 Sulphuric acid of 1.83 specific gravity, and two and a quarter times 

 as much water. 



The tent was placed over a tree ; the bottom flaps of canvas were 

 covered with earth, and a porcelain lined kettle was placed on the 



