222 ENTOMOLOGY. 



Sulphur for mites; borax for cockroaches. 

 Ointments and carbolic soap for lice. 

 Salt, hot water, ashes, dust, soot. 



Various devices and machines for applying powders or 

 liquid preparations. 



Paris Green and Lender". Purple. These arsenical preparations may 

 be used dry when mixed with cheap flour in the proportion of 1 to 

 25 parts, or wet mixed in the proportion of | to 1 pound of the pow- 

 der with 40 gallons of water. The London purple is the weaker of 

 the two powders; but is often preferred to Paris green from its 

 cheapness, and because it is more easily diffused, and can be seen 

 more distinctly on the leaves, though its effects may not be observed 

 until two or three days after being applied. 



Petroleum Emulsions. Dilute 1 quart of kerosene oil and 12 fluid 

 ounces of condensed milk with 36 ounces of water. This is emulsi- 

 onized by violent churning, and before being used may be diluted 

 from 12 to 20 times with water. Equal parts of kerosene and con- 

 densed milk may also be thoroughly mixed or churned together, and 

 then diluted ad libitum with water. 



Pyrethrum or Persian Insect-powder. This powder is deadly to most 

 insects, but harmless to plants and human beings, cattle, or horses. 

 It may be applied (1) as a dry powder; (2) as a fume, being thrown on 

 the stove or on a red-hot sliovel or piece of sheet-iron; (3) as an 

 alcoholic extract, diluted; (4) by simply stirring the powder in water; 

 and (5) as a tea or decoction. As a powder it may be mixed with 

 from 10 to 20 times its bulk of wood-ashes or flour, but before use 

 should remain for twenty-four hours with the diluent in an air-tight 

 vessel. (Riley.) One experimenter dilutes the dry powder with only 

 four or five times its bulk of flour in applying to cabbages to kill 

 cabbage-worms 



Spraying-machines. Numerous inventions for applying these 

 preparations on an extensive scale are described in the reports and 

 bulletins of the Entomologist of the Department of Agriculture at 

 Washington; among the most efficacious being spray nozzles* of 

 different kinds, being modifications of the old-fashioned sprinklers 



* The eddy or cyclone nozzle consists of a small circular chamber 

 with two flat sides, one of them screwed on so as to be readily re- 

 moved. Its principal feature consists in the inlet through which the 

 liquid is forced, being bored tangentially through its wall, so as to 

 cause a rapid whirling or centrifugal motion of the liquid, which 

 issues in a funnel-shaped spray through a central outlet in the ad just- 

 able cap. The breadth or height, fineness or coarseness of the spray 

 depends on certain details in the proportions of the parts, and 

 especially of the central outlet. The nozzle was invented by Riley 

 and Barnard. In applying the fluid to trees, an ordinary barrel is 

 used as a reservoir, in which is inserted a force-pump with automatic 

 stirrer. A long rubber hose extends from the pump, and is attached 

 to the spraying apparatus. (Riley.) 



