306 MAINE AGRICULTURAL EXPERIMENT STATION. I907. 



Thirty slat-work crates or drawers each containing about 2^2 

 barrels were made to hold the potatoes while being treated. 

 These were 4 feet 4 inches by 3 feet 7 inches, and 9 inches deep. 

 The sides were made of solid inch board while the ends and 

 bottom was constructed of slats of the same material 1^2 inches 

 wide and placed an inch apart. The interior angles were rein- 

 forced by a triangular strip made by splitting a piece of 2x2 

 from corner to corner. These crates were arranged in vertical 

 tiers of 5 each on opposite sides of the room. To support them 

 while in use 2x4 scantlings were placed upright between the 

 tiers, one near each corner, and securely fastened to the floor 

 and ceiling. Pieces of 2x2 were then spiked crosswise on these 

 uprights in such a way as to support the crates one above the 

 other and to allow their being pulled out when empty like 

 drawers in a cabinet. When in place there was a space of 4 

 inches between the top of the one crate and the bottom of the 

 next above, and a 10-inch open space in the rear of all, thus 

 providing for free circulation of the gas on all sides. In the 

 center of the room between the 2 rows of tiers was an aisle 

 somewhat wider than the length of the boxes. This was pro- 

 vided to facilitate the filling of the crates and to leave an open 

 central space in which to generate the gas. As will be shown 

 later there should be no potatoes directly above the generator, 

 in order that the gas may mix with the air somewhat before it 

 comes in contact with the surface of the tubers. If this is not 

 done there is danger of injuring the germinating qualities of 

 those tubers directly above the generator and in contact with 

 the strong, hot gas as it is given off. Figure 45 shows the 

 appearance of these crates when in position. 



For a generator a small galvanized washtub about 15 inches 

 in diameter at the bottom was placed in the center of the room 

 about a foot from the floor, midway between the 2 lines of 

 crates filled with potatoes. When ready to use 31^2 ounces 

 of potassium permanganate was spread evenly over the bottom 

 of the tub, then 4 pints and 1 ounce of 40 per cent formaldehyde 

 poured over this. 



* Approximately 23 ounces of potassium permanganate and 3 pints of 

 formalin to the 1000 cubic feet. See Bulletin No. 141, p. 89. 



