46 



the top for filling it. We used a liea\\y horse, and placed on the back 

 of the animal an old saddle, Avhicli seemed to relieve his l)ack of any 

 undue strain. IIoAvever, as before stated, the weight was so well 

 balanced on the axle that the outfit was not at all severe on the 

 horse and was drawn Avith apparent ease when the tank Avas from 

 one-half to two-thirds full. 



We had planned to spray early in July, but owing to delay in get- 

 ting the cart completed the first spraying was not given until July 

 14. At that time kerosene emulsion was Ubcd at the rate of 1 part of 

 stock emulsion to 12 parts of water. The nuichine worked perfectly, 

 one man and one pump being sufficient to envelop each tree in the 

 row in a complete fog. In this fog were thousands of hoppers fly- 

 ing from the trees, but unable to escape the spray. This strength of 

 emulsion, however, while it killed the young hoppers, did not per- 

 manently affect the adults. On July 10, therefore, we increased the 

 strength, using 1 part emulsion to 10 of water. This in no way in- 

 jured the trees, nor did it. unfortunately, kill the adults, which were 

 very numerous at that date. 



Learning from the Missouri station that they were using a mechan- 

 ical mixture of kerosene (10 per cent) and water with considerable 

 success, 1 sent for a kero-water pump, which is show^n in figure 2 (at 

 the right) fitted to the platform. The writer has yet to see one of 

 these kero-water machines which pumps true to the indicator. Our 

 experience has been that if the indicator points at 10 per cent one is 

 not at all sure of obtaining that percentage of oil in the water; in 

 fact, he is quite sure not to. ^Mien the indicator of our pump '' in- 

 dicated " 20 per cent we found by actual test that we were pumping 

 10 per cent, and 25 per cent indicated gave only 15 per cent. With 

 the indicator at 30 per cent we obtained 25 per cent, Avhile 50 per cent 

 on the indicator gave nearly 50 per cent by actual test as it came from 

 the nozzles. The indicator's 10 per cent and 15 per cent gave such a 

 small i^ercentage of oil, far below the figure indicated, as to be prac- 

 tically worthless for our purpose. We found, further, that when the 

 oil in the oil tank got quite low the percentage materially changed. 

 For instance, Avith the indicator at 25 per cent Ave i)umped 15 per cent 

 steadily until the tank Avas nearly empty, Avhen test shoAved that Ave 

 were getting only 5 per cent. This inaccuracy and variation is com- 

 mon to all the kero-Avater punjps Avith Avhich I liaA^e had experience, 

 and is a serious objection to their use. Nevertheless, once understood, 

 and frequently tested in the field, these machines may do good service. 



Our kero-water outfit arrived too late in the season to be of real 

 practical benefit. It Avas used August 5 for the first time, and kero- 

 Avater Avith 15 per cent of kerosene was applied. At that date the 

 hoppers Avere becoming decidedly less in number, and, further, the 



