14 Department Cireidar 263, U. S. Dept. of Agriculture. 



pears on the surface of the mixture and as the boiling begins the 

 brown scum will begin to disappear. At this stage the heat should 

 be cut oil' and the entire mixture should be pumped twice under a 

 pressure of about 60 pounds while still very hot. The first pump- 

 ing may be made from the tank into a second container. The second 

 pumping can then be made back into the original container or into 

 barrels or other storage receptacles. 



Heating the mixture is not sufficient to produce an emulsion. The 

 mixture should be boiled, but it is not necessary that the boiling con- 

 tinue more than a few minutes. In pumping, the entire contents 

 should pass through a pressure pump twice. A rotary pump should 

 not be used for the pumping. Stirring will not produce a proper 

 emulsion nor should the mixture be allowed to cool before it is 

 pumped. 



Fio'ure 3 illustrates the outfit which was used for makins: stock 



Fig, 3. — Equipment used for making stock emulsion for experimental sprayini 



emulsion for the experimental spraying. The mixture was boiled 

 on a wood stove and emulsified by the use of a hand pump. With 

 this small outfit a barrel of stock emulsion could be made in half a 

 day. 



The method of preparing the stock enmlsion is so sim})le tliat any 

 grower with the proper equipment can make his own emulsion. By 

 using a galvanized tank of about 200 gallons capacity a 50-gallon 

 barrel of oil, 25 gallons of water, and 50 pounds of soap could be 

 cooked. It is necessary that the tank be large enough to allow for 

 the increase in volume that occui*s during boiling. A power s])rayer 

 does very well for the pumping. AVith such an outfit the suction 

 hose is placed in the boiling mixture and the material may then be 

 pumped into the spray tank. From there it can then l)e ])iim})ed 

 again into barrels. Old hose should be used, as the hot oil mixture 



I 



