28 FUMIGATION FOB THE CITRUS WHITE FLY. 
end of each pole as before, but the two operators station themselves 
with t he 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 Clermont 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 oil*, 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; PI. 
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 posil ion 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 derrick-. These 
men may now tie their hoisting ropes to the braces or hold them 
tightly by band while the other men pull on the guyropes, causing 
the derricks to fall forward, pulling the tent oxer the tree. Five or 
six men may he needed to cover ver\ large seedling trees such as are 
