PRACTICAL HINTS TO NURSERYMEN 121 



moist, but should not be drenching wet. Where only 

 a few trees are fumigated, they are usually stood on 

 the floor in bunches. When the desired number has 

 been placed in the room, and the ventilators have been 

 closed, they are ready for the gas. The chemicals are 

 then prepared and placed, after which the doors are 

 closed, and left the desired length of time. A half- 

 hour is the minimum limit, but thoroughly matured 

 dormant trees are not injured in the least if left an 

 hour. The chemicals should be prepared and used 

 strictly in accordance with the directions given in 

 Chapter II. 



Other materials needed. A pickle jar or china dish 

 holding from two to four quarts is best adapted for 

 holding chemicals for the generation of the gas in 

 ordinary houses. Sometimes a larger vessel, such as a 

 snuff- jar, is needed. A liberal supply of small manila- 

 paper bags holding a pound or more are necessary. 

 Where the amount of cyanide needed is known, it can 

 be weighed, placed in manila bags, and kept in an 

 air-tight can or other enclosure ready for use. Care 

 should be taken not to weigh too much cyanide at a 

 time, as the bags become saturated with moisture if 

 long exposed to the air. It is best to weigh the cyanide 

 at night or early in the morning, or even during the 

 noon hour, rather than have it standing around for 

 several days. A glass beaker, holding from a pint to 

 a quart, with a graduated scale on the side in ounces, 

 will be required for the acid and water. A supply of 

 acid should be kept in a carboy or other vessel. It 

 should be drawn in an ordinary glass, china, or agate 

 pitcher, as needed. For immediate use, a supply of 



