INSECTICIDES, PREVENTIVES, AND MACHINERY. 449 



The best of the pumps that were supposed to spray definite 

 proportions of oil and water, failed under ordinary field con- 

 ditions, and after a period of popularity have been almost entirely 

 abandoned. 



Of late, chemists have found means to treat the crude petro- 

 leum, both of parafifine and asphaltum base, in such a way as to 

 make it readily and directly miscible with water. These soluble 

 petroleums are still unduly high in price, and are sold under such 

 names as Kill-O-Scale, Scalecide, and the like ; but they have 

 really solved the problem of using petroleum safely and effec- 

 tively. They are essentially winter washes, but may be safely ap- 

 plied at almost winter strength (one to twenty-five) any time after 

 October i, and at full strength (one to twenty) up to the time 

 that the buds open in the spring. The range of usefulness for 

 summer work has not yet been determined , but the way having 

 been opened, it seems probable that this most effective of insecti- 

 cides will shortly be developed so as to make it safe on all sorts 

 of plants at all times. 



Kerosene is a distillate from crude petroleum, and equally fatal 

 to insects. It lacks the lighter oils and the paraiiline, vaseline, 

 asphaltum, and other heavy remnants, and hence evaporates com- 

 pletely and rather rapidly. I have used it in a fine spray, undi- 

 luted, on trees and plants in full foliage without causing the least 

 injury, and it has been so used by others ; but it is a dangerous 

 application in careless hands, and not to be resorted to unless 

 there is danger to the tree from the insect attack. Made into an 

 emulsion so as to mix with water, it has a great range of usefulness 

 wherever an active contact insecticide is needed. Kerosene 

 emulsions or preparations which make the oil readily miscible 

 with water may now be purchased from several manufacturers of 

 insecticides, or may be made as follows : 



Hard soai>, shaved fine Yz pound 



Water i gallon 



Kerosene 2 gallons 



Dissolve the soap in boiling water ; warm the kerosene and 

 add the boiling hot suds to it ; then churn with a force-pump for 

 a few minutes, and we get first a milky appearance, which yields 

 rapidly to a cream, and this to a soft, butter-like mass. When 

 cold, it will adhere to glass without oiliness, and the emulsion 



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