Spray Calendar. 57 



to fonii on the surface of the liquid. If no pellicle forms, more 

 milk of lime should be added. 



Frepaiiiig large amounts—The foregoing directions apply to 

 cases where small quantities of the mixture are needed for more 

 or less immediate use. If spraying is to be done upon a large scale, 

 it will be found much more convenient and economical in every way 

 to prepare what is known as stock solutions of both the copper and 

 lime. To prepare a stock solution of copper sulphate, procure a 

 barrel holding 50 gallons; weigh out 100 pounds of copper sulphate, 

 and, after tying it in a sack, suspend it so that it will hang as near 

 the top of the barrel as possible ; fill the barrel with water, and in 

 two or three days the copper will be dissolved ; now remove the sack 

 and add enough water to bring the solution again up to the 50- 

 gallon mark, previously made on the barrel. It will be understood, 

 of course, that this second adding of water is merely to replace the 

 space previously occupied by the sack and the crystals of copper 

 sulphate. Each gallon of the solution thus made will contain two 

 pounds of copper sulphate, and, under all ordinary conditions of 

 temperature, there will be no material crystallization, so that the 

 stock preparation may be kept indefinitely. 



Stock lime may be prepared in much the same way as the copper 

 sulphate solution. Procure a barrel holding 50 gallons, making a 

 mark to indicate the 50-gallon point; weigh out 100 pounds of fresh 

 lime, place it in the barrel and slack it; when slacked, add sufficient 

 water to bring the whole mass up to 50 gallons. Each gallon of 

 this preparation contains, after thorough stirring, two pounds of 

 lime. 



When it is desired to make bordeaux mixture of the 50-gallon 

 formula, it is only necessary to measure out three gallons of the 

 stock copper solution, and, after thorough stirring, two gallons of 

 the stock lime; dilute each to 25 gallons, mix, stir, and test as al- 

 ready described. One test will be'sui^cient in this case. In other 

 words, it will not be necessary to test each lot of bordeaux mixture 

 made from the stock preparation, provided the first lot is perfect, 

 and no change is made in the quantities of the material used. Spe- 

 cial care should be taken to see that the lime milk is stirred thor- 

 oughly each, time before applying. As a final precaution, it will 

 be well to keep both the stock copper sulphate and the stock lime 

 tightly covered. 



