5 
two such vessels being placed in the larger rooms. Under each a 
carpeting of old newspapers was placed. A number of vessels had 
to be discarded because of cracks, which would be dangerous in 
view of the heat generated by the process. 
The house having been put in a state of readiness for the experi- 
ment, and the vessels for the charges having all been placed in their 
proper locations, the requisite amount of water indicated by the table 
already prepared (twice the amount of the acid) was poured into each 
of the different vessels. Following this, the proportionate amount of 
acid for the different rooms was added to the water in the vessels, the 
addition of the acid developing a high temperature. The cyanide hav- 
ing been previously weighed out in half-pound lots and put in small 
thin paper bags, was distributed through all the different rooms in the 
proper amounts. The division of the bags for the fractional weights 
was made at the time the bags of cyanide for each charge were placed 
by the side of the vessels to receive them. The house was now in 
readiness to be fumigated. Coats and hats and everything needed out- 
side were removedgand two persons went to the garret of the house and 
quickly placed the bags of cyanide in the already combined water and 
acid, passing rapidly down to the next floor and repeating the operation, 
and so on until the basement was finished and the escape was made 
from the basement door to the street. 
The preparation of the different rooms, getting their cubic contents, 
fixing the vessels, and preparing the charges consumed, in a house of 
this size, nearly three hours. The gas was left to do its work for three 
hours longer. The house was then opened cautiously, the doors and 
windows of the lower floor first, then proceeding by easy stages through 
the different floors to the garret. The gas coming out of the house 
when the first doors and windows were opened was in enormous vol- 
ume, showing that the house had retained it very effectually, and escap- 
ing from the house it was distinctly recognizable by its odor at a dis- 
tance of over half a block. The windows of the adjoining houses were 
kept closed during the process of airing out. One of the assistants 
who attended to the aerating of the house was rather too precipitate in 
going to the upper rooms and breathed more or less of the gas, but 
‘suffered no worse results than a rather severe headache which lasted for 
several hours. 
The results of the fumigation were eminently satisfactory; no 
living insects could be found in the house. The roaches, by thou- 
sands, had come out from their hiding places in a vain effort to 
escape, and had rushed to the cracks under doors and windows, and 
had there perished. Sometimes they had the appearance of being 
alive and about to run, and a touch was necessary to demonstrate 
that they were dead, having been arrested instantly while in motion, 
