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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 comparatiyely large 

 spaces. A number of cells sometimes have to be treated as a unit. 

 In one case a corridor 90 fe6t long, extending in ctipolas to a height 

 of 50 feet, and inclosing with its connecting cells an aggregate of 

 140,000 cubic 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 imi)orted, 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 ubiqtiity 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 tised to an 

 ounce by weight of cyanide; thus for a 3-potind 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 onl}^ is meastired 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 weiglit 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 tj'ing 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 tlie 

 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 safet}^, 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 i3rocedure 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. 



