100 The Spraying of Plants. 



copper with 15 pounds of triturated sulphur, and 10 pounds 

 of air-slaked lime." 



Circular No. 4 appeared in July ; it was entitled " Treatment 

 of the Potato and Tomato for the Blight and the Rot." Among 

 the formulas given, only two require notice. That for the Bor- 

 deaux mixture produced a still more dilute preparation. The 

 directions were to " dissolve 4 pounds of sulphate of copper in 

 16 gallons of water ; in another vessel slake 4 pounds of lime 

 in 6 gallons of water." This was a decided improvement on 

 the formula published during the preceding April. Among 

 the dry applications is found a " Blight powder " ; this was 

 made by mixing " 3 pounds of anhydrous sulphate of copper 

 with 97 pounds flowers of sulphur." It has not come into 

 general use. 



The annual report of the Section of Vegetable Pathology for 

 1887 l is full of suggestion and encouragement. The white rot 

 and the bitter rot of grapes are described, they having been 

 identified in this country for the first time. Copper compounds 

 are recommended for their treatment. New formulas are intro- 

 duced, as the old ones had not given satisfaction in all cases. 

 The manufacture of eau celeste is described as follows : 



"In 2 gallons of hot water, dissolve 1 pound sulphate of 

 copper ; in another vessel dissolve 2 pounds ordinary carbonate 

 of soda ; mix the two solutions, and, when all reaction has 

 ceased, add 1| pints of liquid ammonia ; when desired for use, 

 dilute to 22 gallons." 2 This preparation has become better 

 known under the name " modified eau celeste." 



To prevent injury to the young shoots, the following solution 

 is recommended : u Dissolve 1 pound sulphate of copper in a 

 gallon of hot water, to this solution add liquid ammonia, a little 

 at a time, until all the copper is precipitated ; the liquid is then 

 turbid and blue in color. Add 2 or 3 gallons of water, and let 

 stand to settle. Then pour off the clear liquid which contains 

 sulphate of ammonia the compound which causes the burn- 

 ing of the leaves. Then pour upon the precipitate left in the 

 vessel just enough liquid ammonia to dissolve it. ... When 

 required for use dilute to 22 gallons." 3 



1 Ann. Bept. U. S. Com. of Agric. 188T, 323-397. 



2 Formula of M. Masson, Progres Agricole, 1887, July. 

 Progres Agricole et Viticole, 1888, April 29. 



