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Sulphuric acid should not come in contact with the hands or with 
the clothes, as it will severely burn the flesh and ruin the clothes. It 
should not be placed in metal receptacles, as it will soon eat them 
thru. 
Fumigate in the cooler parts of the day, and avoid, if possible, a 
temperature above 60° or 65° F., since at a higher temperature the 
plants are more liable to be injured. 
The foliage of plants to be fumigated should be perfectly dry, 
otherwise it will absorb the gas and be burned. 
The best-shaped jar, when using two ounces of cyanide to a jar 
is one four or five inches in diameter and about nine inches high. 
If more cyanide is to be used in each receptacle larger jars must be 
used. 
Always put the water into the jars first, adding the acid later. 
Never pour water into the undiluted acid. 
After placing the sulphuric acid in the jars the bags of cyanide 
should be put in as soon as possible, for any delay will interfere with 
the proper reaction of the chemicals owing to the fact that the acid 
acts most powerfully when it first unites with the water. The manner 
of putting the bags into the acid is also important. They should 
not be held a foot or more above the jars and dropped in, as the 
bags may be thrown out by the reaction. Each bag must be care- 
fully laid in the jar, but the fumigator must not lean over the jar 
as he does it, nor remain near it to watch the reaction. After a few 
fumigations the operator often becomes less attentive to the pre- 
scribed directions and precautions. This tendency should be 
promptly checked, the utmost care and caution being uniformly nec- 
essary. 
Carbon Bisulfid 
Carbon bisulfid is used as a fumigant for aerial planl-lice. for 
root-lice and root-maggots, and for weevils in seeds. For methods 
to be followed in treating the first class mentioned, see page 112. 
For root-lice and root-maggots, a small hole is made in the ground 
near the plant, and into it is poured a small tablespoonful of the liq- 
uid. The hole is then promptly closed and the maggots are killed by 
the fumes. The carbon bisulfid should not be poured on the plant 
above ground nor directly on the roots. For weevils, the seed should 
be placed in a tight box or bin, space being left at the top for a pan 
or other shallow dish for the carbon bisulfid. This should be used 
at the rate of one ounce to 60 cubic feet of box space, and the box 
should be kept closed for 24 hours. The vapor given ofif, being heav- 
ier than air, descends, killing all insects present without injuring 
the seed. 
