HANDLING LETTUCE AND CELERY. 19 



as well as slow. The crates generally are spaced an inch or two apart 

 in order to facilitate the circulation of air, but even greater spacing 

 would be by no means sufficient to equalize the rate of cooling 

 throughout the car. The heavier cold air settles in the lower part 

 of the car, and the entire lower layer therefore cools off rather quickly, 

 though not as rapidly in the center as near the ice bunkers in each end. 

 The upper layers, especially the top tier, cool off more slowly. This 

 fact is particularly noticeable in cars that have been closed for only 

 a few hours after being loaded. When the doors in these cars 

 are opened the air near the floor feels cold, but that near the ceiling 

 is often unbearably hot. This heat sometimes causes serious damage. 

 The leaves turn light yellow, and as this injures the appearance of 

 the celery and is recognized on the market as an indication of lessened 

 vitality, crates containing celery with yellow tops' are discounted 

 accordingly. In general practice, when the car is unloaded the crates 

 from the top of the load are purposely mixed with the more attractive 

 crates of the lower tiers, in order to make them sell at a fair price. 

 If the celery in the top crate is very yellow, however, the entire ship- 

 ment is discounted 25 to 50 cents per crate below the price which 

 it would have brought had there been no "yellow tops." 



Celery from the Manatee section of Florida is shipped largely in 

 crates 12 inches in depth. This is regarded as the standard crate 

 in that section. In other localities, notably around Sanford, the 

 10-inch crate is the standard. The minimum freight rate is quoted 

 on 350 crates regardless of size, and when the larger crate is used 

 this number makes a load that reaches within 8 or 10 inches of the 

 top of the car. Naturally, it is more difficult to lower the tempera- 

 ture in this car than in a car loaded with the 10-inch crates, where 

 more space is left between the top of the crates and the roof of the 

 car. In both cases, however, there is often serious damage due to 

 slow cooling. In this connection, attention should be called to the 

 desirability of the adoption by the growers of a standard-sized crate 

 for all sections of the State. 



OUTLINE OF CELERY-PRECOOLING EXPERIMENTS. 



In order to determine the effect of precooling upon the temperature 

 of the celery while in transit, two experimental cars were procured 

 in March. Twelve electric thermometers were placed in various 

 parts of the load in each car as in the case of the lettuce cars, and 

 one of the cars was precooled. The bunkers of the precooled car 

 then were topped off . sufficiently to replace the ice that was lost 

 by melting during the time it was being loaded and precooled, but 

 no more ice was added during its entire trip. The other car was 

 shipped in the usual manner, i. e., under full refrigeration. In 



