FUMIGATION OF NUKSERY STOCK. 81 



floor, should be lined with 2-ply cyclone paper, or other heavy raw-hide 

 or building paper, over which a good quality of 4 in. flooring is laid. 

 The roof may be covered with roofing paper, tarred or gravelled. In some 

 cases shingles are used, and in one instance I know of a house where a 

 galvanised roof is used. The doors should be 3J x 6J ft., double, refri- 

 gerating style, hung with three heavy strap-iron hinges, and bolted at 

 top and bottom with a lever such as is used on doors of refrigerators. 



Fig. 16. — Plan of Slat Floor. 



In most cases it is advisable to lock each door when the gas is being 

 generated. 



One of the most convenient and useful houses I have used has a 

 ground plan of 12x16 ft. It is divided into three sections, one large 

 room 1.2 x 12 and a small room 4x8 ft., with a store room 4 x 4 ft. The 

 floor plan and general outline of this building are shown in figs. 15 and 17. 

 It has a double floor with paper between, and a space of l^ft. as shown in 

 the figure, d d, above which there is a slat floor, on a level with the bottom 

 of the door, as shown at a and b. In the store room, c (fig. 16), the 

 floor is solid. In the construction of this building the slats should be 

 made in sections, so they can be removed. It will be found necessary 

 to clean the lower part of the house from time to time, as more or less 

 dirt will rattle through the slats upon the floor. The slats are used so 

 that the gas can be generated underneath the nursery stock, thereby 

 obtaining a more general diffusion. The jar containing the chemicals 



1 ^"""^ 



1 







1 



1 



Fig. 17. — Genp:iul Plan of Floor. 



can be placed under the slats through the small doors at the base, (/ (7, 

 and very often it is advisable in a large room to have two doors of this 

 character so that the chemicals can be divided and the gas generated on 

 opposite sides. We have found that good results are obtained where this 

 plan is followed. The small doors used for ventilation purposes, c c (fig. 15), 

 can vary in size to meet the conditions. The door entering the store 

 room need not be double, and 8 x 6 ft. is a convenient size. 



G 



