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. 13 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 



