24 SPRAYING CROPS 



mixture is properly made, a thin pellicle, looking like 

 oil on water, will begin to form on the surface of 

 the liquid. If no pellicle forms, more milk of lime 

 should be added. 



"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 con- 

 venient and economical in every way to prepare what 

 are known as stock solutions of both the copper and 



Testing Bordeaux Mixture 



The saucer or plate method and the knife method 



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 5o-gallon mark, previously 

 made on the barrel. It will be understood, of course, 



