Dec, 1909.] SOME APPLE DISEASES. 135 



This is known as the 3-3-50 formula. In a 3-4-50 formula, 3 

 pounds of copper sulfate and 4 pounds of lime are used to each 

 50 gallons of water. 



The copper sulfate can be readily dissolved in hot water. If 

 several hours are to intervene before it is needed for use, it is 

 conveniently dissolved by being placed in a sack and suspended 

 in cold water in a barrel or other wooden vessel. As a matter 

 of convenience the number of gallons of water used should be 

 the same as the number of pounds of copper sulfate to be dis- 

 solved. 



The lime should be slowly slaked in another vessel. Hot water 

 insures a more complete slaking, but it is not essential. For the 

 sake of convenience the lime milk may be diluted so that it makes 

 as many gallons of solution as there were pounds of lime. A 

 gallon of either solution should now contain a pound of the sub- 

 stance dissolved. These strong solutions should not be poured 

 together, but should serve as stock solutions, and if properly 

 protected from evaporation may be kept for several weeks or even 

 the entire season. 



To make a barrel of 3-3-50 Bordeaux, three gallons of the stock 

 copper sulfate should be diluted to 25 gallons, and in another 

 vessel three gallons of the lime milk similarly diluted. The two 

 solutions may now be poured together, stirring constantly. The 

 resulting solution should have a large excess of lime, but if there 

 is any question as to the purity of the lime, or, if a safe-, 

 guard against mistakes is desired, when all of the copper sulfate 

 solution and about two thirds of the lime milk have been com- 

 bined the mixture should be tested for excess copper by the addi- 

 tion of a few drops of potassium ferrocyanide solution. If there 

 is an excess of copper sulfate present a conspicuous brown pre- 

 cipitate will be formed. The absence of this indicates that the 

 amount of lime already added has been sufficient to combine with 

 all of the copper sulfate. The remainder of the lime solution 

 should now be added as a further safeguard. The above direc- 

 tions may, of course, be variously modified to suit conditions, but 

 the copper sulfate should always be made very dilute before the 

 addition of the lime. 



It has been customary to advise that Bordeaux should never be 

 used after standing overnight, since when the precipitate has 



