32 



sheets of canvas, rounded at the corners and sewed with overlap- 

 ping- double seams. Seven of these were 50 X 60 feet in diameter, 

 ten were 40 X 48 feet, and twenty were 32 X 38 feet. There were 

 also ten conical tents eleven feet in diameter at the base, used for 

 the smallest trees. For lifting- these tents into place there were 

 two 14-foot scantlings for the smaller sheet tents, two 20-foot lifts 

 made of 2 X 4 scantling-s, spliced and reinforced, and two 30-foot 

 masts. Each pole when in use was fitted with a pulley, throug-h 

 which ran a three-fourths inch rope, and was also provided with 

 from one to three guy-ropes with which to direct its motions as 

 the tents were being lifted and drawn into place. For trees twelve 

 feet in height, or less, one 14-foot pole was the most convenient 

 lift. For those between twelve and eighteen feet one 20-foot pole 

 was commonly used unless the top of the tree was unusually broad, 

 when two were necessary. For still larger trees the 30-foot masts 

 were used, one or both according to the size of the tree. 



Description of the Operation. — The method of handling the 

 tents and of liberating the gas was substantially the same as that 

 described and amply illustrated in Professor Woodworth's Bulletin 

 122, already referred to (pp. 20-30). Different phases and varia- 

 tions of the operation are illustrated in Plates II. — VI. At- 

 tempts were made at first to fumigate very large trees, even when 

 two tents of the largest size were necessary, one being drawn over 

 the other so as to lap upon it several feet. (See Plate V.) 



In ordinary work with one pole three men were required to 

 handle the tent, but when two poles were used a fourth man was 

 necessary. Two others were needed for the process of fumigation, 

 making a squad of six for the entire operation. 



For peach- and apple-trees of medium size, that is, 12 to 18 

 feet in height with a spread of 8 to 15 feet, a squad of three men 

 with a single 20-foot lifting pole did the work most expeditiously. 

 The pole was leaned against the tree on the side opposite that 

 from which the tent was to be raised, and one end of the rope run- 

 ning through the pulley at the top of the pole was thrown over the 

 center of the tree and made fast to the nearest edge of the tent. 

 The pole man then hauled the tent upward to the pulle3% or at 

 least high enough to clear the tree, and fastened his rope, took the 

 guy-rope hanging from the top of the pole, moved forward far 

 enough to get the necessary leverage and drew the tent over the 

 tree, the other two men of the squad, one at each side of the tent, 

 spreading it over the sides of the tree and adjusting it to the top. 

 This operation is illustrated by Plate II., taken just as the men 

 have begun to pull the tent forward over the tree. After the tent 



