INSECTICIDES, PREVENTIVES, AND MACHINERY. 437 



suspension a long time, and eventually settle into a pasty mass at 

 the bottom. 



In spraying with any of the arsenical poisons the water serves 

 only as a carrier to spread the material over a greater area. 

 When the water evaporates, it leaves a thin film on the surface, 

 and this serves as a protection against leaf-feeding insects for a 

 longer or shorter time. On a rough leaf, the particles will lodge 

 in the depressions and may remain for months ; on a smooth leaf, 

 the first heavy shower may remove almost everything. The finer 

 the material, the better it settles into the leaf tissue, and from that 

 view-point Paris green is the poorest and arsenate of lead the 

 best of the stomach poisons. Glucose or molasses at the rate 

 of two quarts per barrel adds materially to the sticking qualities 

 of any mixture ; but some plants, like cabbage, have the leaves 

 so smooth and waxy that even that is not sufficient. 



The following resin mixture has been found effective : 



Stock Solution. 



Pulverized resin . 5 pounds 



Concentrated lye i pound 



Fish or other cheap animal oil . , i pint 



Water 5 gallons 



Place the resin, oil, and one gallon of hot water in a kettle and 

 boil until the resin is thoroughly softened. Then dissolve and 

 add the lye slowly, stirring constantly until thoroughly mixed. 

 After this add four gallons of water, and boil until you get a 

 clear amber-colored liquid which will mix readily with cold water. 

 It will take about two hours to prepare this solution, and if there 

 are less than five gallons when through boiling, add water enough 

 to bring it up to that amount. 



It is only on cabbage, cauliflower, and similar waxen-leaved 

 plants that this mixture is needed, and for use take one part resin 

 mixture and sixteen parts water ; stir thoroughly, add three parts 

 milk of lime in the same way, and finally Paris green at the rate 

 of one pound in eighty gallons of the solution. This must be 

 used at once, for if allowed to settle it cannot be satisfactorily 

 mixed again ; the order of mixing also must be closely followed 

 to prevent a flocculent precipitation and consequent formation of 

 an insoluble soap. 



The addition of soap of any kind at the rate of one pound per 



