12 BULLETIN 927, U. S. DEPARTMENT OE AGRICULTURE. 
The trays of freshly prepared material are placed in the drier at 
the upper and cooler end and are gradually pushed toward the lower 
and hotter end as they become partially dried. When the drier is 
filled the edge of the tray on the lowest runway is placed flush with 
the edge of the hot-air opening, the next tray above projects about 
2J inches over it, and so on to the top, as shown in figure 6. The 
arrangement at the opposite end is, of course, exactly the reverse. 
When thus arranged the edges of the trays act as baffle boards, 
breaking up the column of hot air arising through the floor and 
forcing it to pass between the successive tiers of trays. Any good- 
sized strongly constructed stove and any fuel which is available 
may be used. The arrangement of the pipe, as shown in the draw- 
ing, permits the maximum use of the heat produced by the fuel 
burned. The stove room may be temporarily partitioned off by 
walls of rough boards. Instead of a stove, a coil of steam pipe 
may be used for heating. The walls, floor, and ceiling of the drier 
may be of matched flooring, siding, sheet iron, or beaver board. 
A drier of the size shown will provide a little more than 300 
square feet of drying space and will accommodate approximately 
TOO pounds of wet seed at one charge. If all the wet seed which is 
produced in one day is left in such a drier overnight it will be dry 
the following morning. It is estimated that the entire cost of such 
a drier will not exceed $250. 
The Bureau of Chemistry has developed and successfully applied 
the so-called trayless drier (fig. T) to the drying of vegetable 
products. This drier consists of a tight wooden box in which a 
double series of dumping trays is mounted. The total drying area, 
consisting of 32 square feet, is divided into four compartments, 1 
foot wide and 4 feet long, each being provided with two dumping 
trays, as shown in the illustration. The drier is made of white 
pine lined with compo board to prevent the leakage of air. The 
lower front of the drier is fitted with two doors, through which 
the finished material can be removed. The air is heated by a fur- 
nace and is supplied directly by a blower fan which delivers about 
2,000 cubic feet of air a minute against a static pressure of a 1-inch 
water gauge. A furnace, such as is used for heating houses, is large 
enough for a drier of the size described. Where steam is available 
steam coils can be used for heating. Devices for charging the drier 
or for discharging the finished material are not shown, but could 
easily be constructed, thereby making the operation more or less 
automatic. The lower compartment could be made hopper shaped 
and fitted with a gate valve discharging the seed to a conveyor or 
oscillating apron. In operation the wet material is placed in the 
upper tray for about half an hour. The tray is then tilted and the 
charge is dumped to the tray below and a fresh charge put into the 
