10 CIRCULAR 17 5, U. S. DEPARTMENT OF AGRICULTURE 



pump or other pump, the materials being forced through a spray 

 nozzle at 150 to 200 pounds pressure. 



No. 2a. — Same as formula 2, except that the quantity of spreader 

 used was varied as indicated in Table 6. 



No. 3. — Miscible oil. 



Per cent 

 Water 4. 5 



Dry soap 4. 7 



Cresol 5. 6 



Oil 85.2 



The ingredients must be accurately measured by volume. The 

 soap used is a potash fish-oil soap, such as that described in formula 

 10. The quantity of water in it must first be determined, and enough 

 added to make up the amount called for above. The cresol (cresylic 

 acid, 97-99 per cent, pale) is then added, and these ingredients are 

 stirred, with gentle heat if necessary, until they are thoroughly mixed 

 and uniformly clear. The oil is then added and thoroughly stirred 

 in. The resulting miscible oil should be as clear as the pure oil, and 

 no sediment should separate out other than the few impurities in the 

 soap, nor should any free oil collect at the top. An oil of asphalt 

 base must be used with this formula. 



No. 4-. — Miscible oil. Made according to the Washington State 

 College formula. 7 



Per cent 



Potash fisli-oil soap 5 



Cresylic acid (technical cresol) 4 



Oil 91 



The ingredients are measured by volume. The fish-oil soap is 

 dissolved in the cresylic acid, and the resulting " Cresoap " is then 

 dissolved in the oil. The soap used should have the following 

 specifications : 



Parts 

 by weight 



Fish oil 10 



Caustic potash 2 



Water 5 



No. 5. — Lubricating oil-fatty acid emulsion. This formula was 

 suggested by Siegler and Popenoe. 8 



Oil gallons 2 



Fatty acid pounds— 2% 



Caustic potash (commercial) ounces 9 



Kerosene i pints 2% 



Water gallons— 2 



The fatty acid used is a commercial mixture containing crude 

 lauric acid, and is known as " double distilled coconut fatty acid.'' 

 The caustic potash is dissolved in the water, and the fatty acid is 

 melted and poured into the caustic solution. The oil is then added 

 and the mixture heated to the boiling point. It is then removed from 

 the fire, the kerosene is added, and the mixture is pumped twice to 

 emulsify it. 



7 Melander, A. L., Spuler. A., and Green, E. L. oil sprays; their preparation and 

 use for insect coxtrol. Wash. Agr. Expt. Sta. Bui. 184, p. 19. 1924. 



8 Siegler, E. H., and Popenoe, C. H. some insecticidal properties of the fattt- 

 acid sebies. Jour. Agr. Research (1924) 29:259-261. 1925. 



