FUMIGATIOX OF CITRUS TREES. 



23 



inches and prevents the slopping of acid through the hole. A lead- 

 lined cover fits into the top of this tube. This opening in the cover 

 is for use in filling the jar. Very few metals will withstand sulphuric 

 acid without corroding. For this reason all the common types of 

 faucets are practically worthless for drawing acid. In fact there is 

 no faucet on the market that is altogether satisfactory for this pur- 

 pose. A manufacturing firm on the Pacific coast has experimented 

 extensively along this line, but without any marked success. This 

 difficulty has been met in an entirely practical manner by attaching a 

 three-quarter-inch copper or iron pipe to the lower side of the jar and 

 regulating the flow of acid by means 

 of a large pinchcock placed on a short 

 piece of rubber tubing at the end of 

 the pipe (fig. 5,1,4} an( l ^) • The flow 

 of acid is rapid and easy to control. 

 Pure rubber is most satisfactory, and 

 a fresh piece should be substituted 

 about every other night. 



The water is drawn from a faucet. 

 In order that this mav be drawn on 

 the same side of the cart as the acid, 

 an elbow pipe of the character shown 

 in Plate IV, figure 1, is required. The 

 faucet should have an opening of about 

 three-fourths inch to allow a heavy 

 flow, and should be of such a type that 

 a half-turn will give it a full opening. 



As fumigation is usually conducted 

 at night, a torch is placed on the 

 front of the cart to furnish a light by 

 which to measure the acid and water: 

 another, on the elevated platform, is 

 convenient for the man weighing the 

 cyanid. 



This style of cart is entirely practicable for almost all fumigation 

 work. The chemicals can be measured quickly and accurately with- 

 out any slopping of acid or water. A glass graduate with a capacity 

 of 16 or 32 ounces, preferably the latter, is essential for measuring 

 acid and water. A kind having elevated rings in the glass has been 

 found most satisfactory for night work. The man handling the acid 

 should wear rubber gloves. Cotton gloves are convenient for hand- 

 ling cyanid. 



Some fumigators have preferred to use a horse-drawn wagon 

 equipped for carrying the chemicals rather than a handcart. This 

 has resulted in a number of very original combinations. The most 

 67330°— Bull. 90—12 3 



Fig. 5. — Earthenware acid jar with attach- 

 ments for field use; 1, Jar complete; ^,inside 

 view of lead-lined cover showing tube at 

 center; S, copper top for opening in cover; 

 1, pinchcock; 5, method of attaching iron 

 pipe to jar, and rubber tube on end of pipe 

 with pinchcock attached. (Author's illus- 

 tration.) 



