In case of a large range of houses opening into each other it is 
best to separate them into several sections, by tacking up building 
paper or oiled cloth so that each section may be fumigated separately 
and at different times. The work may thus be done with greater 
ease and care, and with less danger to the plants. When all the 
larger cracks and openings have been stopped up, if the house is 
quite old or loose it is well to wet the roof on the outside just before 
fumigating. The water will fill the cracks between the glass and 
will assist in making the roof tight. 
METHOD OF MAKING THE GAS. 
The materials required are 98 per cent cyanide of potash, best 
secured in 5 or 10 pound cans at 35 to 40 cents a pound, and commer- 
cial sulphuric acid at 3 to 4 cents a pound. 
‘For an ordinary house or frame, good vessels for liberating the 
gas are 15 or 2-gallon earthen jars of as small diameter as possible 
so as to insure the immersion of the cyanide of potash when it is 
dropped into the acid. One jar should be used to about every 50 feet 
in length of such houses as described in order that the gas may be 
quickly distributed when set free. When the jars are placed in 
position the next step is to arrange to lower the paper bags contain- 
ing the desired amount of cyanide into the jars, from the outside. 
This is best done by passing a cord through a hook or screw-eye 
attached to the roof over each jar in such a manner that when the 
string or strings are loosened from the outside the bags of cyanide 
will be lowered into their respective jars, as shown in fig. 3. When 
the strings are ready, divide the amount of cyanide to be used into 
parts corresponding to the number of jars. Do each part up ina 
couple of thicknesses of ordinary newspaper and put in ordinary 
brown paper bags, and attach the bags to the strings, as shown in 
fig. 3. While the jars are empty test the arrangement to see if- 
it works satisfactorily. After each bag is suspended in place, the 
other end of the string securely fastened where it can be reached 
from the outside, and the arrangement tested, move the suspended 
bags to one side so they will be out of the way while putting the 
water and acid in the jars. When this is done, pour into each jar 
an amount of water about equal to the bulk of the potassium cyanide 
in the bag. Eight ounces of cyanyde will require about half a pint 
of water. The sulphuric acid should then be poured in until steam 
rises from the water. This would require for a pint of water about 
a pint and a half of acid. It is not necessary, however, to measure 
the acid as the evolution of steam indicates when the right amount 
has been poured in. Always put the water in first and then pour in 
the acid. As soon as this is done place the bags over their respective 
jars. In order to prevent injury to foliage in case it is very near the 
