TRANSPORTATION OF CITRUS FRUIT FROM PORTO RICO 
11 
return No. 2 'tween-decks/' In Figure 6 an average difference 
throughout the trip of about 12 degrees between the temperature of 
the ingoing and outgoing air will be noted. In other words, the 
cold air was heated up 12 degrees by the fruit in the hold. The 
fruit lost this heat and was therefore cooled down, as is shown in 
the curve of average fruit temperatures (fig. 6) . The temperature of 
the air was reduced and much of the heat removed as it passed over 
the brine pipes on its return to the mixing chamber. In this way 
an average of about 5 degrees of heat was absorbed from the air 
by the brine before it got back to the mixing chamber. There 
was an increase of from 5 to 7 degrees in the temperature of the 
air as it passed through the mixing chamber, as shown by a com- 
parison of the air temperatures of the intakes and outlets. This in- 
Fig. 6. — Average ingoing and outgoing air, average fruit temperatures in No. 2 
between-decks, and outside air and sea-water temperatures on the first trip 
crease was brought about through the friction of the fans and by 
heat which came through the bulkhead forming the outside wall of 
the mixing chamber. The air temperature was reduced 12 to 15 
degrees after leaving the mixing chamber and passing over the brine 
pipes before it entered the hold. 
The effect on the fruit of the temperature conditions obtaining 
in these two refrigerator holds was shown on the inspection of the 
cargo made on arrival at New York. The average percentage of 
rot in the oranges shipped under refrigeration, including unculti- 
vated oranges, was 1.7 per cent, and with grapefruit it was con- 
siderably less, being below 1 per cent for the boxes inspected. 
To obtain data on the value of refrigeration in the carrying of 
good fruit, eight boxes of oranges from a well-cultivated grove were 
shipped from San Juan to New York, four boxes being under re- 
frigeration and four under ventilation. The results of this experi- 
ment show that the percentage of rot in the fruit under ventilation 
was 3.7, whereas with that under refrigeration it was 1 per cent. 
