20 



BULLETIN 601, IT. S. DEPARTMENT OF AGRICULTURE. 



other words, this check car was topped off with ice after loading, and 

 reiced in transit at the regular icing stations. A representative of 

 the Department of Agriculture accompanied these cars and took 

 accurate temperature records from time to time. The average 

 temperature of the load in each car was computed from the 12 readings 

 taken at each recording point. 



TRANSIT TEMPERATURE RECORDS. 



Figure 14 shows the average temperature of the celery in each car 

 from the time it was loaded until it reached the market. The tem- 

 perature of the outside air during the entire trip is shown also. The 

 divisions at the left indicate degrees of temperature. The bottom 

 divisions indicate the time in days. The small circles on each of the 



Fig. 14 . — Diagram illustrating the average temperatures ( ° F . ) of carloads of precooled and nonprecooled 

 celery in transit from Florida to New York, season of 1915. 



curves are placed at the intersection marking the time that the read- 

 ing was made and the temperature at that time. The lower curve 

 represents the temperature of the precooled car and the upper curve 

 that of the nonprecooled car. The irregular curve running through 

 the chart marks the outside air temperature. 



The precooled car was loaded about noon on March 3, but was not 

 cooled until the following morning, at which time the temperature 

 of the car was only about 50° F. The first part of the curve illustrates 

 this precooling period and shows the length of time required to pre- 

 cool the car and the temperature of the car at the time it was shipped. 

 This point, about 37° F., was known to be lower than the ice would 

 hold it, but as this was the first car shipped under initial icing it 

 seemed desirable to be on the safe side by starting with a low tem- 

 perature. The diagram shows very clearly how the temperature 



