February, '17] BURGESS AND GRIFFIN: BANDING MATERIALS 133 



Massachusetts, and Connecticut on all kinds of trees and no injury to 

 the trees resulted, and excellent results were secured. Many tests 

 were also made by Mr. C. W. Collins and C. E. Hood of the Gipsy 

 Moth Laboratory to determine the effect of using bands of different 

 widths and thicknesses as well as to compare the results of these sub- 

 stances with other banding materials. One sample, however, proved 

 better than the other on account of its being a little softer, which made 

 it easier to handle in the guns when the temperature was low. 



In gipsy moth work, banding is usually begun in April and many 

 days the weather is rather cold. The sample which gave the best 

 results contained the following materials. 



(a) A high boiling neutral coal tar oil having a density of about 1.15 

 at 20°C. 



(b) A soft coal tar pitch. 



(c) Rosin oil of the grade known as first run "Kidney" oil. 



(d) Ordinary commercial quick lime. 



A stock mixture was first made up in large quantities as follows : A 

 weighed quantity of the coal tar pitch was transferred to a ten-gallon 

 steam jacketed kettle, which was equipped with a stirring arrangement 

 operated by a motor, and heated until thin enough to run. Then 

 twice its weight of the coal tar neutral oil was run in and the mixture 

 well stirred, thus giving a product which could be poured and worked 

 after it had cooled off. This will be referred to as the "Pitch-neutral 

 oil mixture." 



The quick lime was slaked with a small amount of water, so that the 

 resultant product would be a dry powder. This was passed through a 

 sieve having ten meshes to the inch. 



The tree banding material was mixed as follows: 5 lbs. of the " pitch- 

 neutral oil mixture," 16 lbs. of the coal tar neutral oil and 4 lbs. of 

 slaked lime were weighed into the mixing kettle previously referred to, 

 and the stirrer started working. When the contents had become of a 

 uniform consistency, 20 lbs. of rosin oil were added and about ten 

 minutes later 10 lbs. more of the coal tar neutral oil. At the end of 

 twenty-five minutes from the time the rosin oil was added, the stirring 

 was stopped and the material dumped into tubs. It was now rather 

 thin and was allowed to stand for two days by which time it had set 

 into a semi-solid cake. Two pounds of the coal tar neutral oil were 

 stirred into each 50 lbs. of this mixture in order to give it the desired 

 oily surface. The product was now ready for use. 



The physical properties of the material can be varied through quite 

 a large range by varying the proportions of coal tar neutral oil and 

 "pitch-neutral oil mixture," and also by varying the amount of rosin 

 oil and lime. The addition of more coal tar neutral oil makes the 



