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CIRCULAR 4 2 2, U. S. DEPARTMENT OF AGRICULTURE 



The eaves of the warehouses, wherever possible, were sealed from 

 the inside with elastic roofing cement (fig. 16). This material was 

 inexpensive, durable, and not difficult to apply. In some instances it 

 was found necessary to seal the flashing around the eaves and the 

 skylights from the roof. This sealing was satisfactorily done by 

 pasting strips of a tough paper over the metal flashing where it 



joined the brick wall, by 

 using a paperhangers* 

 paste. This method of 

 sealing from the roof is 

 shown in detail in figure 

 17. It should be empha- 

 sized, however, that ordi- 

 narily a most effective 

 seal was obtained from 

 the inside, using the elas- 

 tic cement, and it is rec- 

 ommended that, when- 

 ever possible, the eaves of 

 tobacco warehouses be 

 sealed from the inside. 



Many of the windows 

 in the warehouse shown 

 in figure 12 had loose 

 frames and were in poor 

 condition, generally, and 

 it was found advisable to 

 seal the entire window 

 space with a gasproof tar 

 paper. The paper was 

 cut to fit and tacked to 

 the sills and facing. A 

 wooden strip was then tacked over the paper along the window 

 frames and elastic roofing cement used for sealing along the edges. 

 This method of sealing windows is shown in figure 18. 



The sliding doors of the warehouses presented a difficult problem in 

 sealing. A sealing mixture was developed, consisting of 4 parts of 

 asbestos to 1 part of calcium chloride and sufficient water to make a 

 stiff dough. This mixture was prepared in a large shallow box 

 mounted on a small truck and was plastered around all edges of the 

 doors, effecting a complete seal. The calcium chloride preserved the 

 moisture in the asbestos and prevented cracking before the end of the 

 experiment. This mixture had the advantage of cheapness and ease 

 of application, and was easily removed from the doors at the end of 

 the fumigation. In figure 19 is shown a door of a tobacco warehouse 

 sealed for fumigation. 



When the sealing operations were completed, the warehouses were 

 fumigated with hydrocyanic acid. The method of introducing the 

 fumigant is shown in figure 20. The copper pipes passing through 

 the brick walls of the warehouses can be seen, and in the foreground 

 are V2 -norse P ower motors and compressors used to provide the re- 

 quired pressure in the cylinders, each of which contained 75 pounds 

 of the fumigant in liquid form. 



Figure 15. — A ventilator situated near the floor of 

 a tobacco warehouse, showing the manner of 

 sealing for fumigation. A portion of the card- 

 board is shown adhering to the ventilator, over 

 which the tar paper had been sealed. 



