CIRCULAR 462, U. S. DEPARTMENT OF AGRICULTURE 



Temperature readings were obtained by means of thermocouples 

 inserted in the various containers. These were made of no. 36 copper 

 and constantin wire and were thoroughly varnished and dipped in. 

 rubber cement to waterproof them. A thermocouple was placed in 

 the center of each bale or hogshead by first making a hole in the 

 outside case or carton and inserting a steel spike three-eighths of an 

 inch in diameter. After withdrawing this spike the thermocouple 

 was easily inserted by looping it over the end of a slender steel rod 

 and thrusting it into the bale to the required depth. The rod was 

 then withdrawn leaving the thermocouple in the desired position. In 

 the case of the hogshead a thermocouple was placed in the center, an- 



DAYS 



Figure 2. — Rate of cooling of the center of bales of four different types of cigar tobacco 

 when placed in a cold room at 10° F. 



other midway between the outside and the center, and a third one- 

 fourth the distance to the center. Two couples each were placed in 

 the four bales, one in the center and another midway between the out- 

 side and the center. The electromotive force was measured by means 

 of a potentiometer and converted into degrees Fahrenheit. After in- 

 stallation of the thermocouples the tobacco was moved into a Low-tem- 

 perature room of the cold-storage plant which was maintained at an 

 average temperature of 10° F. Figures 2 and 3 show the results 

 obtained in this experiment. In order to simplify the graph the 

 temperature reading for the center of the bales only is given in figure 

 2. The tobacco half way to the center of each bale cooled down from 

 a half a day to a day more rapidly than the center, but otherwise the 

 curve was much the same. The reading for the half-way point in 

 the hogshead was left out of figure 3 for the same reason. 



