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For an ordinary lK)Use (jr frame, gooil vessels for liberating the gas are Ij or 2 

 gallon earthen jars of as small diameter as possible, so as to insure the immersion of 

 the cyanide of potash when it is dropped into the acid. One jar should be used to 

 about every 50 feet in length of such houses as described, in order that the gas may 

 be quickly distributed when set free. When the jars are placed in position the next 

 step is to arrange to lower the jiaper bags containing the desired amount of cyanide 

 into the jars, from the outside. This is best done by passing a cord through a hook 

 or screw-eye attached to the roof over each jar in such a manner that when the 

 string or strings are loosened from the outside the bags of cyanide will be lowered 

 into their respective jars, as shown in fig. 6. When the strings are ready, divide the 

 amount of cyanide to be used into parts corresponding to the number of jars. Do 

 each part up in a couple of thicknesses of ordinary newspaper and put in ordinary 

 brown paper bags, and attach the bags to the strings, as shown in fig. 6. While the 

 jars are empty test the arrangement to see if it works satisfactorily. After each bag 



Fig. G.— Violet liouse i^rt-pared for fumigation (from Woods ik iJur^ett i 



is suspended in place, tlie other end of the string securely fastened where it can be 

 reached from the outside, and the arrangement tested, move the suspended l)ags to 

 one side, so they will be out of the way while putting the water and acid in the jars. 

 When tliis is done, pour into each jar an amount of water about equal to the bulk 

 of the potassium cyanide in the bag. Eight ounces of cyanide will require about 

 half a ]iint of water. The sulphuric acid should then be poured in until steam rises 

 from the water. This would require for a pint of water about a pint and a half of 

 acid. It is not necessary, however, to measure the acid, as the evolution of steam 

 indicates when the right amount has been poured in. Always put the water in first 

 and then jiour in the acid. As soon as this is done place the bags over their respec- 

 tive jars. In order to prevent injury to foliage in case it is very near the jars, it is 

 a good plan to surround each jar by some protection. A section cut from a roll of 

 building paper is effective. The paper naturally rolls into a tube and is very con- 

 venient for this puri)ose. Tlie pieces may l>e laid togetlicr and tied when not in use, 



