2 BULLETIN 1290, U. S. DEPARTMENT OF AGRICULTURE 
States moves b}^ water. This means of transportation for citrus 
fruit is becoming more important, however, not only from the outly- " 
ing islands of the United States, but from California and Florida 
as a supplement to rail shipment. Until recently most of the citrus 
fruits shipped into or from this country by water were handled in 
ventilated holds or in regular cargo holds which were not refriger- 
ated. There has always been more or less loss with this method of 
shipment, depending upon the condition of the fruit when shipped, 
the season of the year, the temperature maintained in the holds, and 
the methods of handling. It would seem that low temperatures com- 
bined with proper methods of handling the fruit would be as valu- 
able in ocean as in land transportation. It was to determine the 
value of refrigeration on shipboard and to work out the best methods 
for loading and handling the fruit in refrigerated holds that the 
experiments described herein were undertaken. It was thought prob- 
able, also, that information gained as to the best methods for ship- 
ping citrus fruit would be applicable to the shipment of apples, 
pears, and other fruits both in intercoastal trade and for export. 
EQUIPMENT AND CONDITIONS OF THE EXPERIMENTS 
The investigations here described were conducted in cooperation 
with a steamship company operating between New York and Porto 
Rico, on a twin-screw steamer equipped for both freight and pas- 
senger service. The vessel makes the trip in approximately three 
and one-half days, completing a round trip to and from New York 
every three weeks. It arrives in San Juan on Wednesday forenoon 
and discharges its cargo, remaining there until Thursday night. It 
then proceeds around the island, calling at ports and discharging 
and receiving cargo, and returning to San Juan the following Tues- 
day or Wednesday morning, to finish loading. On Thursday it starts 
on the return trip to New York, where it arrives early Monday 
morning, leaving again for Porto Rico the next Saturday. 
In this vessel five cargo-carrying compartments have been insu- 
lated and refrigerated for carrying fruit. The entire capacity of 
these holds was about 35,000 boxes of citrus fruit, using the standard 
Florida box as a unit of measurement. The insulation was heavy, 
consisting of 4 inches of cork, three layers of seven-eighths-inch 
matched lumber, and eight layers of paper, with a 3-inch air space be- 
tween the first outer layer of boards and the ship ? s side. The hatches 
to these compartments were fitted with insulated covers, of construc- 
tion similar to that of refrigerator doors, built in sections and fitted 
with gaskets, which were supposed to make them air-tight when the 
covers were in place. 
The cooling system was a combination of brine and forced-air cir- 
culation, three ammonia compressors of 18 tons capacity furnishing 
the refrigeration. The insulated compartments were cooled by air 
forced over brine pipes, which were placed against and along the in- 
sulated sides of the compartments, extending the entire length and 
from floor to ceiling. A board partition, or apron, about 9 inches 
from the sides of the compartments formed a continuous duct 
through which air was circulated and in which the brine pipes were 
inclosed. This apron was pierced at regular intervals by a number 
