524 CITRUS FRUITS AND THEIR CULTURE. 



phate has dissolved, fill up the barrel to the fifty gallon 

 mark. When thoroughly stirred, each gallon will con- 

 tain two pounds of copper sulphate. 



Carefully slack 100 pounds of good, fresh lime, place 

 it in a second barrel and add water to make fifty gal- 

 lons. This solution will contain two pounds of lime to 

 each gallon, when thoroughly agitated. 



In making up the spraying mixture from these stock 

 solutions, stir well, then dip out three gallons of the 

 copper sulphate solution and dilute to twenty-five gallons 

 with water in one barrel and place two gallons of the 

 lime solution in a second barrel and dilute to twenty- 

 five gallons. Then pour these together in the barrel of 

 the spray pump as already directed. 



If sufficient lime is not put into the mixture, there 

 is danger of injuring the foliage. To obviate this, the 

 mixture should be tested before using and if deficient in 

 lime, more should be added. One of three tests may be 

 used. Dip out a small quantity in a shallow dish, hold 

 it up between the eye and the light and blow the breath 

 gently into it. If a thin pellicle forms on the surface, 

 there is sufficient lime present, but if this pellicle is not 

 seen, lime must be added until it becomes visible. Second, 

 dip a clean steel blade into the solution and hold it there 

 for a minute or more. If a 'thin film of copper forms on 

 the blade, more lime must be added. Third, prepare a 

 solution of ferrocyanide of potash by dissolving an ounce 

 of the substance in four or five ounces of water. Dip out 

 a portion of the Bordeaux mixture into a shallow, white 

 porcelain dish and allow a drop or two of the ferrocya- 

 nide of potash solution to fall into it. If a brownish red 

 coloration is noted, lime must be added until no color 

 is seen. 



