IXSECTICIDES, PREVENTIVES, AND MACHINERY. 439 



generally with only small satisfaction. It is a deadly poison 

 and effective against insects, but, unfortunately, is just as injurious 

 to plants, and the limit of effectiveness as between plants and 

 insects is so narrow as to render its use undesirable in most cases. 

 It is valuable only in those few instances w^here it is desirable to 

 poison a prepared food or bait, and its use is not advised, except 

 in special cases where particular directions are given. 



The Bordeaux mixture, though primarily a fungicide, has 

 excellent insecticide qualities in certain cases, and, among others, 

 it seems to be almost a specific against flea-beetles. This is an 

 important feature, and renders its use doubly valuable on pota- 

 toes, egg-plants, tomatoes, and other crops susceptible to flea- 

 beetle attack. Either Paris green, London purple, or white 

 arsenic may be added to the Bordeaux mixture where a com- 

 bined insecticide and fungicide is desired, but Paris green is the 

 best. London purple only can be added to the ammoniacal 

 carbonate of copper, since the ammonia in the fungicide acts as 

 a solvent to the arsenic in Paris green. Either of the fungicides 

 may be treated as replacing water, in determining the amount of 

 the insecticide to be used. 



The formula for the Bordeaux mixture is as follows : 



Sulphate of copper 6 pounds. 



Quick-lime 4 pounds. 



Water 22 gallons. 



Dissolve the copper sulphate in one gallon of hot water, and 

 in another vessel slake the lime with a gallon of water ; add the 

 milk of lime slowly to the copper solution, stirring constantly, 

 and strain through a sieve or coarse gunny sack ; finally, add 

 twenty gallons of water, and the mixture is ready for use. This 

 gives the standard full-strength mixture, and half strength or 

 other proportionate strengths are produced by simply adding 

 more water. 



The ammoniacal solution of copper carbonate, or "cupram," 

 is made as follows : 



Carbonate of copper 5 ounces. 



Ammonia water (twent>'-six per cent, strength) . 3 quarts. 

 Water 30 gallons. 



