OIDIUM OR POWDERY MILDEW OF THE VINE. 343 



The data given are the prices and the results of the Chancel test, 

 column C, and of the microscopical examination. The Chancel test is 

 the determination of the amount of settling that occurs when 5 grams 

 of sulfur are allowed to stand in a cylinder after shaking up with 25 

 cubic centimeters of ether. The number represents the percentage of 

 the height of the cylinder occupied by the sulfur after settling. It is 

 a very convenient and quick method of testing the fineness of the sul- 

 fur. (See fig. 17.) 



30 28 4 16 8 



FIG. 17. Comparative volumes of 5 grams of different sulfurs. 



No. 30. Sublimed Sulfur, Chancel No. 66.8 $70.00 



No. 28. Sublimed Sulfur, Chancel No. 50.8 ... 41.00 



No. 4. Sublimed Sulfur, Chancel No. 40.0 55.00 



No. 16. Ground Sulfur, Chancel No. 51.6 32.00 



No. 8. Ground Sulfur, Chancel No. 38.0 47.50 



The numbers corresponding to good commercial sublimed sulfur 

 are 50 to 70 ; those of the finest quality show 75 to 90. Powdered or 



