FUNGICIDES 



25 



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 solu- 

 tion thus made will contain 2 pounds of copper sul- 

 phate, and, under all ordinary conditions of tempera- 

 ture, there will be no material recrystallization, 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 slake it. When slaked, add 

 sufficient water to bring the whole mass up to 50 gal- 

 lons. Each gallon of this preparation contains, after 

 thorough stirring, 2 poimds of lime. 



"When it is desired to make Bordeaux mixture 

 of the 50-gallon formula it is only necessary to meas- 

 ure out 3 gallons of the stock copper solution, and, after 

 thorough stirring, 2 gallons of the stock lime ; dilute 

 each to 25 gallons, mix, stir, and test as already de- 

 scribed. One test will be sufficient in this case. In 

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

 Bordeaux mixture made from the stock preparations, 

 provided the first lot is perfect and no change is made 

 in the quantities of the materials used. Special care 

 should be taken to see that the lime milk is stirred 

 thoroughly each time before applying. As a final pre- 

 caution it will be well to keep both the stock copper 

 sulphate and the stock lime tightly covered." Care 

 should be taken that there is always some excess 

 of lime. 



A special advantage of the Bordeaux mixture is, 

 that arsenicals may be added to it, making a combined 

 insecticide and fungicide. Apparently arsenate of 

 lead is the most satisfactory for this purpose. Added 

 to Bordeaux mixture at the rate of 2 pounds to 50 



