METHODS OF HANDLING TENTS. 27 



The element of heat due to the inixiiig of the acid and water is rec- 

 ognized as an important factor in generating the gas. According to 

 C. P. Lounsbiiry " very nearly the maximum amount of heat is evolved 

 when equal volumes of acid and water are used, and he advises against 

 the use of more than 2 volumes of water to 1 of acid. 



The point in question is one of those now under investigation in 

 California by agents of this Bureau. Until conclusions are reached 

 the writer would recommend that the chemicals be used in the propor- 

 tion of 1 part of cyanid, 1 part of acid, and 3 parts of water, or 1-1-3. 

 This formula is recommended for the present on account of results of 

 experiments reported herein and upon which the table given in the 

 appendix is based, being obtained with an average of 3 parts of water 

 to 1 of acid. Future experiments may justify the California prac- 

 tice from the standpoint of danger to the foliage from the use of the 

 smaller amounts of water. In the experience of the writer as reported 

 herem, the injury to the foliage has been too slight to show any rela- 

 tion to the proportion of the chemicals. 



PROCEDURE. 

 METHODS OF HANDLING TENTS. 



Sheet tents. — Octagonal sheet tents, or covers, are placed in position 

 over trees by means of the changing poles and derricks which have 

 been described. A tree which measures in extreme height between 

 30 and 35 feet can be covered and made entirely ready for the genera- 

 tion of the gas in less than two minutes if the work is not interfered 

 with by the too close planting of trees. Smaller trees usually require 

 from one to two minutes, according to size. When the changing poles 

 are used (Plate II, figs. 1, 2; Plate III, figs. 1-5) m covering small 

 trees, one man on each side of the tree places the ring over the end of 

 his pole if catch rings are used, or if not, makes a double fold of the 

 cloth over the end of the pole and makes a half-hitch over it with the 

 rope to prevent it from slipping off. With the pointed end of the 

 pole on each side about opposite the center of the tree they then raise 

 the end of the pole and attached tent about 8 feet, or until the pointed 

 ends hold without slipping, and, holding on to the rope, step forward 

 and away from the tree and pull the tent into position. Some opera- 

 tors prefer, after attaching the tent to the end of the pole, to stand with 

 one foot on the pointed end and raise the pole entirely by means of the 

 rope. Knots tied in the ropes at convenient intervals near the end 

 are of great assistance in pulling. If the trees are so large that they 

 require tents too large and heavy for handling by two men and yet 

 not large enough to require the use of derricks, a third man may be 

 employed to advantage. The edge of the tent is made fast to the 



« Agricultural Journal (Cape Town), 1902, p. 4. 



