45 



used aud \yhere an intelligent man superintends tlie work, a consid- 

 erable saving may be effected by mixing the raw materials as needed. 

 Arsenate of lead is a combination of arsenate of soda (four ounces) 

 with acetate of lead (eleven ounces). These materials should be 

 separately dissolved in wooden pails, in water enough to do it com- 

 pletely. Then one solution may be poured into the other, stirred 

 thoroughly for a few moments and the combination is arsenate of 

 lead. If allowed to stand, a white precipitate will settle to the bottom, 

 and represents the poison itself. If the combination is diluted to 

 make from fifty to seventy-five gallons of water, the settling will be 

 slow, and practically the entire material may be sprayed without any 

 stirring. That is ajiother advantage, because one part of the mix- 

 ture will not be very poisonous and another practically harmless, as is 

 likely when Paris green is used and the mixture is not kept suffi- 

 ciently stirred. It is important, if the arsenate of lead is to be made 

 as used, that the chemicals employed should be of good quality. This 

 point must be insisted upon, because failures have resulted from im- 

 pure chemicals. The acetate of lead is especially liable to contain sub- 

 stances that will interfere witli proper combination. 



As for contact poisons, fish oil soap will reach more cases than any 

 one other material, and in most instances it will pay to buy the soap 

 ready made up. There are several brands on the market that answer 

 every purpose, and almost every dealer in insecticides has some reason-. 

 ahlj good material of this character. If it is desired to obtain the 

 cheapest mixture and to be absolutely certain of an even compo- 

 sition, the soap may be readily made according to the following 

 formula, first recommended by the Xew York (Geneva) Station: 



Caustic soda 6 pounds. 



Water 1% gallons. 



Fish oil 22 pounds. 



Dissolve the caustic soda in ^'arm water, warm the oil until it is 

 thoroughly fluid, then pour the oil slowly into the soda solution, 

 stirring thoroughly and constantly until the combination is complete. 

 Complete and thorough stirring is essential to success. A good grade 

 of caustic soda should be used, -say 75 per cent, or over. Fish oil of 

 almost any kind will answer and it need not be refined. The amounts 

 given will make forty pounds of soap, and "the cost, at the market price 

 of materials, will be a trifle less than 3 cents per pound. Twenty- 



