36 FUMIGATION METHODS 
the yard are placed cross-bars, as shown in the illus- 
tration. ‘The arrangement of the ropes can be under- 
stood from a study of the figure. 
The heaviest rope is attached to the top of the tent 
with double pulleys. Along the lower edge, on the 
FIG. I13—THE PREBLE FUMIGATOR, AS USED IN 
CALIFORNIA ORCHARDS 
four sides of the tent, are fastened boards, generally of 
ordinary six-inch fencing, which are called trail boards, 
and from the center of each of these the trail ropes 
pass upward and over pulleys attached to the yard and 
ends of the cross-bars. All these ropes follow the 
yard till near the mast, then passing again over pul- 
leys, they go down to the bed of the wagon and are 
fastened over belaying-pins. The trail ropes pass 
