48 



ensuring rapid solution, is costly. Use crude bichloride and reduce it by 

 pounding to a fine powder, care being taken not to inhale the dust from the 

 chemical. When one pound has been pulverized, divide it roughly into 

 16 equal parts. Provide as many old bottles (white glass preferable); 

 put one part of the powder into each, and fill them up with hot water. 

 Shake or roll them about occasionally until dissolved. The contents of 

 each bottle added to twelve and a half gallons of water will make a solution 

 ready for use. 



Two hundred gallons of solution will sufiice for the treatment of about 

 fo'rty bushels of potatoes. 



Use solution only once. Formalin vapour and formalin solution are 

 often recommended, but bichloride of mercury has given the best results 

 all round. 



2. Arsenate of Lead. 



Use "Swift's" Arsenate of Lead; it comes in kegs in form of a soft 

 paste. It readily dissolves with stirring. 



3. Paris Green. 



One pound packages are very handy. It does not dissolve, and should 

 be held in suspension by constant agitation. Paris Green is a deadly poison. 



4. Preparation of Bordeaux Mixture. 



1. Shake a quantity of quick lime in one or more barrels and fill them 

 with the paste' almost to the top, keeping the lime covered with water — or 

 the lime surface will dry up and become lumpy and interfere with straining. 



2. Prepare a " stock solution" of bluestone (sulphate of copper) in 

 such concentration that, when using one gallon of (stirred) mixture, one 

 pound of the chemical in solution is contained therein. To do this, dis- 

 solve two pounds of sulphate of copper in two gallons of hot water, and 

 empty the two gallons into a barrel; repeat the process until you have one 

 or two barrels full with the "stock solution". If you take for use one 

 gallon of "stock solution," you will have one pound of copper sulphate. 



Procedure When Making 40 Gals. Spray of the Required Strength. 



To make forty gallons spray, you will require six pounds of copper 

 sulphate with an "excess" of lime, i.e., an amount sufficient to prevent 

 injury to the leaves. Therefore, have a barrel containing some thirty- 



