22 HYDROCYANIC-ACID GAS FUMIGATION IN CALIFORNIA. 



the end of the poles. TVhen ready to throw a cover, the machine is 

 drawn opposite the tree, the arms are lowered until their ends are 

 suspended beyond the outer edge of the tree, cables are then let down 

 from the end pulleys and run through two series of rings in the tent, 

 after which the tent is raised to the end of the derricks. These rings 

 are so placed that when the cable is raised about one-third of the tent 

 is gathered up in a series of folds. The derricks are then erected 

 and the tent cables released, when the tent will fall over the tree. 



This operation is quite rapid as well as less wearing to the trees 

 and tents than the use of poles or derricks. Although slower and more 

 expensive than the use of poles in covering small trees, it is easily 

 superior to derricks in covering large ones, such as seedlings, especially 

 where so closely set that the branches interlace. 



SUPPLY CART AXD SUPPLY WAGOX. 



An apparatus of some sort is required in carrying from tree to tree 

 the chemicals necessary in fumigation. The idea of using a two- 

 wheeled pushcart originated with the San Bernardino County outfits, 

 where this method has been used for several years. Observation of 

 its use convinced the writer that in most places the employment of 

 a properly equipped handcart is the most practical method available 

 for carrying the chemicals. Extended effort has been made to equip 

 such a cart in a manner suitable for convenient use in the field. The 

 result of this effort is shown in Plate IV, figure 1, the make-up of 

 which has been so improved over the original as to resemble it but 

 little. As purchased, the cart -bed consists of a plain box fitted with 

 a two-shaft handle. This handle is removed, and is replaced by a 

 tongue having an enlarged link-shaped iron about a foot long firmly 

 attached at the end. This link-shaped handle is very convenient in 

 field work. The scales for weighing the chemicals are placed on a 

 platform above the center of the box. The ordinary kind having a 

 free scoop and using weights is most convenient; 1, 2, 4, 8, and 16 

 ounce weights are required. The cyanid is contained in a tin-lined 

 box in the rear half of the cart, while the acid and water are placed 

 in the front end. A 10-gallon keg firmly attached in a horizontal 

 position to the bed of the cart is a very convenient receptacle for the 

 water. A galvanized-iron basin, like that shown above the keg, 

 having an opening at the boitom fitting into the bung of the keg, 

 makes a very satisfactory funnel for filling the latter. The acid may 

 be held in an earthenware jar or a lead-lined tank, with cover firmly 

 attached to prevent slopping. 



By way of a cover for the earthenware jar, a lead-lined lid (fig. 5) 

 which fits tightly within the top has been used. At the center of this 

 lid is an opening about 6 inches in diameter, around the circumference 

 of which is attached a leaden tube which extends downward several 



