OILING METHODS 59 



"One hundred and fifty gallons of crude carbolic 

 acid are heated in an iron tank having a steam coil 

 with steam at 50 pounds pressure. Two hundred 

 pounds of finely crushed and sifted common rosin are 

 dissolved in the heated acid and then 30 pounds of 

 caustic soda dissolved in six gallons of water are added. 

 There is a mechanical stirring rod attached to the tank. 

 The product is ready in a few minutes, yielding 

 about 3^ barrels. ... As a mosquito larvicide it is 

 used by spraying an aqueous emulsion (one part of 

 larvicide to five of water) over the surface and along 

 the margin of pools and ponds or other mosquito- 

 breeding places so that the resulting dilution of the 

 larvicide has a thin, milky opalescence representing 

 approximately a dilution of 1 to 5000." 



