Blankets and as far as possible all else that comes in contact with the 
prisoners are so disposed as to be most freely exposed to the action 
of the gas; suspension of sleeping blankets by one corner from grat- 
ings forming the floors of galleries is sometimes practicable. The 
exposure is continued as long as circumstances allow, with a minimum 
of two hours. 
The procedure of the work is kept as simple as possible, and no 
especial difficulty is experienced in treating comparatively large 
spaces. A number of cells sometimes have to be treated as a unit. 
In one case a corridor 90 feet long, extending in cupolas to a height 
of 50 feet, and inclosing with its connecting cells an aggregate of 
140,000 ecubie feet, was treated as one space. Forty-three charges, 
each weighing 3 pounds, were used, and 20 of these were generated in 
cells off a gallery above the main floor. Five-gallon tins, in which 
kerosene oil has been imported, and from which the tops have been 
cut, are generally used for large charges. These are found safely to 
take 3 pounds of cyanide, and to be serviceable for two or three 
usages. Their recommendation is their ubiquity in this country and 
their inexpensiveness. As in orchard fumigation, 2 ounces by meas- 
ure of water and 1 ounce by measure of sulphuric acid are used to an 
ounce by weight of cyanide; thus for a 3-pound charge of the latter, 
3 pints (United States measure) of acid are added to 6 pints of water. 
When a space necessitating the employment of many generating 
vessels is to be treated, as was the case in doing the corridor above 
mentioned, the water only is measured directly into the vessels, these 
being then, if not before, placed in the positions desired. The acid 
is measured into small receptacles, as tin basins, placed within an 
arm’s length of the vessels, and the required weight of cyanide for 
each, for convenience in handling laid on a square of cheese cloth, 
mosquito netting, or even newspaper, is also laid within reach. 
Squares of cheese cloth, made bag-like by tying the alternate corners, 
are preferred for holding the cyanide, particularly when the series of 
discharges to be made is a long one. When the time comes to ‘fire, 
an assistant, beginning at the farthest corner from the exit, pours 
the respective measure of acid into vessel after vessel, and when he 
has a start of half a dozen vessels the operator follows, and, with the 
greatest dispatch compatible with certainty in action and care to 
avoid splashing, drops the bags of cyanide into the steaming acid- 
water mixtures. Familiarity with the work, quickness of movement, 
and a cool head are essential to safety, and no person not possessing 
these qualifications should attempt multiple discharges. When the 
series is short the operator himself may attend to the addition of both 
the acid and the cyanide, and even measure the acid directly into the 
water. The objection to following this procedure in long series is 
that the acid-water mixtures may have time to cool, and therefore 
fail to fully react upon the cyanide, particularly the larger lumps. 
