HYDROCYANIC-ACID GAS AGAINST HOUSEHOLD INSECTS. 5 
water and acid and accelerate the chemical action, and there is less 
danger of spattering. Whenever the room is of such size that much 
more than 3 pounds of cyanid must be employed for it, it is perhaps 
better to make two charges of half size for such room. 
PROCESS OF FUMIGATION. 
In the process of generating the gas the water may be measured 
in a glass beaker indicating ounces, or, for convenience, in a pint cup, 
and poured into the generators. The acid, measured in the same 
receptacle, is then slowly and gently poured into the water to avoid 
splashing or boiling. For all ordinary purposes 1} pints of the acid 
and 3 pints of water are sufficient for each pound of sodium cyanid. 
The acid should never be placed in the generators first, as advised by 
some writers, since experience shows that this is dangerous, spatter- 
ing being almost certain to follow. When the acid is poured into the 
water in the jar an ebullition of vapor sometimes arises. Consider- 
able heat is also developed by the addition of the acid. 
When the cyanid, which previously should be broken into pieces 
the size of an egg, is finally dropped into the combined acid and 
water mixture bubbling takes place similar to that produced by a 
red-hot iron dipped into cold water. The generation of hydrocyanic- 
acid gas, the most poisonous gas in common use, begins at once. 
The gas is colorless and has an odor which has been likened to that 
of peach kernels. This odor is decidedly metallic, like that produced 
by striking two pieces of metal together, or of metal against stone. 
If the fumes are inhaled in any considerable quantity they are almost 
certain to prove fatal; hence the necessity of extreme care and the 
advisability of the presence of two intelligent operators in this work. 
It is even advisable, especially when the first fumigation is under- 
taken, that one who has had experience with this method of fumi- 
gation be present to give directions. 
The measuring and preparation of the water and acid in the fumi- 
gating jars should be undertaken in a room with a tile or concrete 
floor if possible, as the strong acid used is apt to injure wooden floors 
or carpets should spilling occur. The jars may then be distributed 
to the different rooms and a bag containing the requisite cyanid 
placed by the side of each. 
The house is now in readiness to be fumigated. Coats and hats 
and everything needed outside must be removed, and preferably two 
persons should then go to the top of the house, taking different rooms 
on the same floor to expedite the process, and place the bags contain- 
ing the cyanid gently into the vessels to receive them. The chemical 
action will begin at once, but the gas will not rise to any extent for 
a few seconds or a quarter of a minute, and there is ample time to 
leave the room quickly without danger of breathing the gas. Having 
