Treatment of Cotton Seed 
35 
best to rotate the seed cylinder so that it comes up toward the front and 
descends at the back of the machine. The motion of the cylinder then 
directs the current of hot air toward the front of the machine where it 
strikes the thermostat. Since the seed are being carried toward the front 
of the machine and upward in the rotating drum, they are being heated by 
the same current of hot air which is playing upon the thermostat. At the 
level of the thermostat the temperature at the back of the oven is 10 to 15 
degrees lower than at the front owing to the direction in which the air in 
the oven is circulating. The temperature at the top of the hood just above 
the cylinder is commonly 1 to 3 degrees C. lower than on the level of the 
thermostat in the front of the machine. In practice, the temperature shown 
by the thermometer inserted through the front right hand corner (Thermom¬ 
eter A) of,the frame is taken to indicate the temperature of the seed: 
As indicated by this thermometer there is a variation of V 2 to 1° C. between 
the temperatures at which the thermostat closes and breaks the heating 
circuit. After the heating circuit breaks, the temperature continues to 
rise 1 to 1 V2 0 C. and after the circuit closes, the temperature continues 
to fall 1 to 114 ° C.; so including this lag there is a total variation of 
air temperature in the oven ranging from 2 y 2 to 4° C. as indicated by 
thermometer A. 
Some of the first lots of seed treated in this machine were ruined because 
of defective operation of the circuit breaker and thermostat. Modifications 
have been made which obviated these earlier defects so that the machine 
now operates in a very reliable manner. After the thermostat has been 
adjusted to give the temperature desired, it is necessary to visit the machine 
only occasionally to oil the bearings. 
The total spatial capacity of the seed drum is 2.6 bu., after making liberal 
allowance for space occupied by the shelves which serve to mix the seed. 
If the quantity of seed treated at one time is not too large, the stirring of 
the seed by the rotation of the seed drum is very satisfactory. The efficiency 
of the machine in mixing the seed and thus assuring uniform heating was 
tested by embedding a small double-handful of seeds which had been stained 
red in the middle of the bulk of seeds to be treated and determining 
the time required for the red seeds to be distributed throughout the larger 
mass of seeds in the rotating drum. In one test, in which 18 pounds of 
dry seed (water content 8.5 per cent) were used, the red seeds had become 
within the lapse of 10 minutes uniformly distributed throughout the entire 
bulk of seeds in the revolving drum. In another similar test, 27 pounds 
of seed, a quantity which filled the drum very nearly half full, were used. 
After three minutes of rotation, the red seeds were present in about equal 
quantities in the middle region of each of the 6 compartments of the seed 
drum, and within 45 minutes, they had become distributed fairly uniformly 
throughout the entire bulk of seeds. Thus, both radial and longitudial 
mixing was found to be very satisfactory when the seed drum is slightly 
less than half full. Other tests showed that when the drum is more than 
half full, mixing is much less satisfactory, because, in a drum of the di¬ 
mensions used in these tests, the seeds bulk up between the shelves and 
the axle and fail to slide off the shelves as the drum rotates. If the shelves 
