86 FUNGICIDES COMBINED WITH POISONS 



pounds of copper sulphate. Allow the copper sulphate completely to 

 dissolve. If it is desired to hurry this part of the process, the sul- 

 phate may be dissolved in hot water, using about 2 gallons and 

 stirring well, and this may then be poured into the barrel and the 

 latter filled up to 25 gallons. In another barrel slake 4 pounds of 

 lump Ume, adding more water and stirring well as the lime dissolves, 

 until there are 25 gallons in the barrel. Then combine the sulphate 

 solution and the limewater by dipping alternately from each into the 

 spray tank. Or, the two may be poured slowly at the same time into 

 the spray tank. It is essential that the mixture be thoroughly strained 

 as it goes into the sprayer. 



On some plants the above formula for Bordeaux mixture is too 

 strong, and should be altered to the following : copper sulphate, 2 

 pounds; lump lime, 2 pounds; water, 50 gallons. The method of mak- 

 ing is the same. 



Bordeaux mixture must be used as soon as prepared. If allowed to 

 stand, it changes in composition. More lime may be added, and the 

 material thus made use of, but this procedure is not recommended. 



Where this material is used in large amounts it is convenient to 

 prepare separate stocks of copper sulphate solution and lime " putty.'* 

 Kept separate, they will not deteriorate. Dissolve the copper sulphate 

 in water at the rate of 1 pound of the sulphate to 1 gallon of 

 water. One gallon of this concentrated solution will then equal 1 

 pound of the sulphate. To prepare lime putty, place a known weight 

 of lump lime in a flat trough and add just enough water to slake it. 

 When it is all slaked, see that it is spread out evenly and cover with an 

 inch or so of clear water, to exclude the air. It will be easy to figure 

 out the number of square inches of putty to remove in order to have 

 the equivalent of the desired weight of lump lime. Do not make the 

 mistake of weighing out this putty and considering that a given weight 

 is the equal of the same weight of lump lime. 



Arsenate of lead may be combined with diluted Bordeaux mixture ; 

 but the better plan is to add it to the limewater before the final mixing. 

 The poison should first be well mixed with water, so as to make a 

 thin paste, in order that all of it may find its way into the final mix- 



