368 Report of the Mycologist of the 



different proportions for use on different plants. For spraying 

 cucumbers and melons we recommend the use of a mixture con- 

 taining one pound of copper sulphate, two-thirds of a pound of 

 fresh lime and eight gallons of water. This formula is known as 

 the " l-to-8 formula/' which means that each eight gallons of 

 Bordeaux mixture contains one ponnd of copper sulphate. In a 

 1-to-ll formula, one pound of copper sulphate is contained in 

 eleven gallons of Bordeaux mixture, and so on. This simple 

 method of designating the strength of Bordeaux mixture was 

 devised by Beach.* 



Copper Sulphate. 



Blue vitriol and blue stone are other names for copper sulphate. 

 It is put on the market in three forms: (1) in large crystals, (2) 

 in granulated form, and (3) in powdered form. The granulated 

 form is the most satisfactory because it is cheaper than the pow- 

 dered form and dissolves more readily than the large crystals. 



Copper sulphate, in quantities of from fifty to one hundred 

 pounds ought not to cost more than five cents per pound. In 

 barrel quantities it can be purchased in New York city for four 

 and one-half cents per pound and perhaps less. Since it will 

 keep indefinitely it is advisable to buy in large quantities in 

 order to get wholesale rates. It is poisonous. 



Dissolving the Copper Sulphate. 



Select a wooden vessel (never use an iron vessel) and put into 

 it a quantity of water equal to about one-half the quantity of Bor- 

 deaux mixture desired. A barrel having a capacity of about fifty 

 gallons is excellent for the purpose and, in fact, this is the vessel 

 most generally used. See that the inside of the barrel is free from 

 sticks,, dirt or anything else which might clog the nozzles of the 

 spray-pump. Fill the barrel about one-half full of clean water. 

 Weigh out the required amount of copper sulphate, six pounds 



*See New York Exp. Sta. Bulletin No. 84, p. 3. 



