February, ^16] SASSCER: FEDERAL INSPECTION FACILITIES 223 



auxiliary tank or generator (B) in which the gas is generated. The 

 pipe leading from the fourth opening to the auxiliary or generator 

 is provided with a gas cock and three enlargements, 4a, 46, and 4c 

 (the latter is not shown in the photograph). Two of these en- 

 largements contain sodium cyanide, and the third glass wool. The 

 object of the sodium cyanide and glass wool is to pick up any free 

 sulphuric acid which may be mechanically drawn from the generator 

 when the gas is permitted to enter the fumigation chamber. The 

 auxiliary or generator (B) is so arranged that it can be used as a gen- 

 erating tank or as a fumigating chamber, by closing the gas cock just 

 above the cylinder. The exhaust pipe which leads from the generator 

 to the small vacuum pump (D) is shown as figure 9. No. 5 is a tubula- 

 ture used in introducing the chemicals into the generator. No. 8 

 is a pipe which carries water to cool the air pump (C), and No. 10 is 

 the cooling pipe for the small air pump (D). No. 11 is the pipe which 

 carries the exhaust from the small air pump, and No. 6 is a combi- 

 nation pressure and vacuum gauge. No. 7 is a rheostat. 



The material to be fumigated is placed in the retort (A), the door 

 closed and clamped, and the air exhausted until the gauge registers 

 about 26 inches; that is, the air in the chamber is exhausted until the 

 pressure is the equivalent of about 5 inches of mercury. At this stage 

 the suction is cut off, and the gas is generated in the auxiliary chamber 

 (B) and introduced into the fumigation chamber through the pipe (4). 

 The gas may be generated in one of two ways. The cyanide may be 

 placed in the jar within the generator, the door closed, and the acid 

 and water introduced through the tubulature (5), or the acid may be 

 placed in the jar within the generator and the cyanide in solution 

 introduced through the tubulature (5). The latter method is pref- 

 erable, especially where a glass tubulature is employed, as it elimi- 

 nates all possibility of breakage of glass by the heat generated from the 

 combination acid and water. In fact, to prevent breakage, it has been 

 found advisable to cool the acid and water, which reduces the yield 

 of gas. Where the cyanide in solution is introduced through the tub- 

 ulature, no heat is generated until the solution comes in contact with 

 the acid in the generator. This method has an additional advantage 

 in that the yield of gas is increased." 



The material to be disinfected may be fumigated in either of two 

 ■ waj's, namely, by generating the gas in the presence of a partial vacuum 

 and holding the vacuum for a definite period, or by generating the gas 

 in the presence of a partial vacuum and returning to normal atmos- 

 pheric pressure upon the completion of the generation. 



