334 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. 



3. An improvement on the last method is the use of a sack from 

 which to shake the sulfur on to the vine. This sack should be made of 

 cloth whose texture is close enough to permit only fine particles of 

 sulfur to pass, but not so close as to require too much labor in shaking 

 out the required amount. A sack about 14 inches long and 5 inches in 

 diameter, holding about 3 pounds of sulfur when half full, is a con- 

 venient size. Somewhat tightly woven grain sacks of good quality are 

 suitable material from which to make them. 



Very good work can be done with sacks of this kind while the vines 

 are small. Their main defects are that they hold very little and much 

 time is wasted walking to the sulfur supply to fill them. They wear 

 out very quickly and the work with them is laborious. They cannot be 

 used while the vines are wet, as moisture on the sacks prevents the 

 sulfur from coming out. 



For large and high vines they are even less suitable than the cans. 

 It is almost impossible to sulfur any part of a vine higher than the 

 workman's head. 



4. The use of small hand bellows similar to that shown in fig. 9, b 

 is a great improvement over the three methods just described. The 

 distribution of the sulfur is much better, the workman less troubled by 

 the sulfur, and every part of the vine can be reached. 



The main defects of these bellows are that they are very tiring to 

 the hands and arms, and as they hold little sulfur much time is wasted 

 in filling them. While not so wasteful of sulfur as the above methods, 

 they use more sulfur than is necessary. 



5. The best knapsack bellows are a great improvement on the hand 

 bellows. These machines are known as "dust sprayers," "sulfuring 

 machines," etc. 



There are several hand "dust sprayers" of American manufacture 

 which were originally designed for the distribution of paris green. 

 The current of air by which the powder is blown on to the plant is pro- 

 duced by a rotary fan. The powder is stirred by various devices in 

 the different machines and blown out of a reservoir through a tin or 

 rubber tube. 



The machines made in Europe specially for the distribution of 

 sulfur differ from the above principally in the method of producing 

 the current of air. This is produced by a valve bellows similar in prin- 

 ciple to the old-fashioned blacksmith's bellows. 



All the available American machines and one of the best European 

 machines were tested this year by the Experiment Station. None of 

 the American machines was found suitable for the purpose. They were 



