Attack by Larvacides 1 75 



results are obtained with a content of not less than 

 fifteen per cent, phenols. In order that the 

 finished product may neither float nor sink 

 rapidly to the bottom, but diffuse through the 

 water uniformly and with fair rapidity, the crude 

 carbolic acid should have a specific gravity of 

 about 0.97. 



The process of manufacture is as follows: 

 One himdred and fifty gallons of the carbolic acid 

 is heated in a steel tank fitted with a steam coil. 

 When the acid is steaming hot, two hundred 

 pounds of powered resin is added and the mixtiure 

 continuously stirred by means of a paddle agitator, 

 until complete solution is effected. Thirty pounds 

 of caustic soda (sodium hydroxide) is dissolved 

 in six gallons of water, and this is added to the 

 resin-carboUc acid mixture. The heating and 

 stirring is kept up for about five minutes, and then 

 a sample of the product is withdrawn, and poured 

 into water. If complete and rapid emulsion 

 restdts, the larvacide is ready and is withdrawn 

 from the mixing tank into shipping drums. If 

 emulsion does not occur, or is incomplete, the 

 heating is continued until a sample emtilsifies 

 satisfactorily. 



Each lot of carbolic acid should be assayed for 

 phenol content. Carbolic acid containing less 



