10 



BULLETIN 480, U. S. DEPARTMENT OF AGRICULTURE. 



TABLE I Correct nozzle pressures for different lengths of hose and sizes 



of tips. 



The tables submitted are actual readings taken in the field, and 

 the nearest to a 5-pound point was taken. Some of the variations 

 can only be explained by the expansion of the rubber hose, which 

 also explains the difference from the friction loss in 1-inch iron pipe. 1 



EXPERIMENT TO DETERMINE THE DISTRIBUTION OF POISON 



ON FOLIAGE. 



In order to determine how thoroughly trees were being sprayed 

 by using the solid-stream method a number of experiments were 

 conducted during the summer of 1916. 



For this purpose a series of ferrotype plates. 14 by 10 inches, 

 were secured and treated with black coach paint so that any spray 

 coming in contact with them could be seen. The plates were num- 

 bered and attached to bamboo poles about 12 feet in length. This 

 was done by splitting the small end of the pole, and after insert ing 

 the plate it was sewed in place securely with copper wire. 



The plates were then placed in different positions and at different 

 heights in trees that were to be sprayed and a record secured of the 

 effectiveness of the work. (PI. IX.) This is a method that can 

 be used by anyone to test the thoroughness of spraying for leaf- 

 eating insects. 



One test was conducted to determine the time required properly to 

 spray a shade tree when the solid-stream method is used. The 

 tree selected was 65 feet in height, and excellent results were se- 

 cured by applying the spray for half a minute. A glance at Plates 

 X and XI shows the thoroughness of the treatment in this test and 

 illustrates the value of this method of spraying when properly used. 



1 See Engineering Work in Towns and Small Cities, by Ernest McCullough, 1906, p. 359. 

 Pumping Machinery, by William M. Barr, 1908, p. 108. 



