42 CIRCULAR 369, U. S. DEPT. OF AGRICULTURE 



Hydrocyanic acid, ethylene oxide, carbon disulphide, chloropicrin, 

 carbon tetrachloride, the mixtures of carbon dioxide with ethylene 

 oxide, methyl bromide, or methyl formate, and the ethylene di- 

 chloride-carbon tetrachloride mixture can all be used for the fumiga- 

 tion of furniture in atmospheric vaults. 



Hydrocyanic acid and the ethylene dichloride-carbon tetrachloride 

 mixture are used most commonly. A dosage of 8 ounces of liquid 

 hydrocyanic acid or its equivalent, or of 14 pounds of ethylene di- 

 chloride-carbon tetrachloride mixture, per 1,000 cubic feet of space, 

 for a period of 12 to 24 hours will give satisfactory results unless 

 wood borers are involved, when the exposure should be at least 48 

 hours. If any of the other fumigants are used, the following dosages 

 should be applied per 1,000 cubic feet of space: Ethylene oxide, 2 

 pounds ; ethylene oxide-carbon mixture, 20 pounds ; methyl bromide- 

 carbon dioxide mixture, 20 pounds; methyl formate-carbon dioxide 

 mixtures, 28 pounds; carbon disulphide, 5 pounds; chloropicrin, 1 

 pound ; or carbon tetrachloride, 30 pounds. 



FURS AND GARMENTS 



The protection of furs and fur and other garments in storage by 

 fumigation is becoming more common. The method consists in stor- 

 ing garments in tight rooms (fig. 35) that are so arranged that they 

 can be fumigated regularly. The garments are fumigated in a small 

 vault (figs. 2 and 27) before being placed in the storage rooms 

 (fig. 36). 



CONSTRUCTION OF STORAGE ROOMS 



The large storage rooms may be of any type of construction that 

 is sufficiently tight for fumigation purposes. Usually they are of 

 concrete or of hollow tile covered with Keen's cement. The surface 

 should be finished with two or three coats of good paint. Large 

 shallow evaporating pans are fastened along the walls near the ceil- 

 ing, or are suspended from the ceiling, but so placed that they are not 

 directly over the garments suspended from the racks. These pans are 

 connected by pipes to the storage tank (fig. 37) containing the fumi- 

 gant. If ethylene dichloride-carbon tetrachloride mixture is used as 

 the fumigant, it can be run into the evaporating pans by gravity or 

 by the use of a small compressor. If any of the mixtures of carbon 

 dioxide with ethylene oxide, methyl formate, or methyl bromide is 

 to be used, the evaporating pans are unnecessary, and a piping sys- 

 tem with one or several spray nozzles or cones should be used instead. 

 The cylinders containing one of these mixtures with carbon dioxide 

 are connected to the piping system outside of the room (fig. 26), 

 and the fumigant is applied by merely opening the valve on the 

 cylinders and allowing the required poundage to be discharged. 



The door of the storage room is usually of the safe or refrigerator 

 type, well gasketed so that it will be airtight. An adequate venti- 

 lating system must be installed, so that the gas can be quickly re- 

 moved after the fumigation. As in the case of small fumigation 

 vaults, the ventilating stack should extend well outside the building. 



In cold climates there should be some means of heating the storage 

 room to at least 70° F. during the fumigation. 



