28 FUMIGATION FOR THE CITRUS WHITE FLY. 



end of each pole as before, but the two operators station themselves 

 with the rope in hand at the foot of their respective poles while the 

 helper raises the end of each pole in turn, so that the operators can 

 use their ropes to advantage. The committee of the C^lermont Horti- 

 cultural Club, of California, in their report heretofore referred to, rec- 

 ommended that four men, or two for each pole, be regularly employed. 

 When trees are close planted or there is fear of breaking branches by 

 changing the tent from one tree to the next, or there is dead wood 

 threatening to tear the tent if simply dragged off, the practice of 

 "skinning it off" will be found to be useful. In this method the 

 attachments of the poles are made at the far side of the tent and the 

 cloth slides over itself as the tent is pulled from one tree to the next. 

 In handling sheet tents by means of derricks (PI. V, figs. 1, 2; PL 

 VI, fig. 1) four to six men can work to best advantage. The writer 

 has, however, with one assistant successfully handled a sheet with 

 26-foot derricks. After placing one of the derricks in the position for 

 raising the tent the guy rope was fastened to a tree while the second 

 derrick was raised. Each operator then held the guy rope by means 

 of a loop through which the elbow was placed, giving the use of both 

 hands while raising the tent with the tackle. Ordinarily two men 

 should not attempt to cover a tree by themselves, particularly if there 

 is a slight breeze. When four men are available for handling sheet 

 tents with derricks, they proceed as follows: The sheet is pulled into 

 position back of the tree to be covered, with the rings located one on 

 each side. The derricks are placed one on each side of the tree, flat 

 on the ground and their bases parallel, either directly opposite the 

 center of the tree or within a distance of 3 or 4 feet back, whichever 

 experience with trees of various sizes and widths of rows may show to 

 be best. Two men station themselves, one at the base of each der- 

 rick with guy rope in hand. The other two men go to the opposite 

 ends of their uprights and raise them to a vertical position with the 

 assistance of the men at the bases, who pull with the guy ropes, stand- 

 ing on the cross pieces as long as necessary to prevent slipping. The 

 second two men now steady the derricks while the first two walk for- 

 ward and take a position for holding them in place by means of the 

 guy ropes. The derricks are now brought to a position where the 

 tops are 3 or 4 feet beyond the vertical in order to prevent the weight 

 of the guy rope from causing them to fall forward prematurely. 

 The two men at the bases of the derricks now attach the hooks of the 

 swinging blocks to the rings of the tent and by means of the tackle 

 raise the front edge of the tent to the tops of the derricks. These 

 men may now tie their hoisting ropes to the braces or hold them 

 tightly by hand while the other men pull on the guy ropes, causing 

 the derricks to fall forward, pulling the tent over the tree. Five or 

 six men may be needed to cover very large seedling trees such as are 



