22 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1909. 
of placing in the refrigerating chamber freshly picked fruits in 
comparison with those that have been exposed to the air several days 
after picking. It is necessary to place the sound fruit in the cold 
fruit chamber soon after it is gathered. Other circumstances also 
influence its keeping qualities. It is much better if the fruit comes 
from older trees; it also appears that sandy soils are not favorable 
to preservation. 
Fruits with a thick skin keep much better than those with an easily 
ruptured covering. The peach, in particular, is one of the most 
difficult of fruits to preserve. M. Loiseau, horticulturalist at Mont- 
reuil, however, has succeeded in keeping this delicate fruit more than 
a month. According to him, it is especially necessary to maintain 
the temperature as constant as possible, varying not more than from 
OF tov C: 
Among the recent applications of low temperatures which have 
been pointed out may be mentioned the use of artificial cold in the 
manufacture of paraffin and viscose. 
Crude petroleum generally contains from 5 to 6 per cent of paraf- 
fin in solution. To obtain this paraffin, the petroleum is distilled 
until it contains from 10 to 25 per cent of paraffin. Then by lower- 
ing the temperature of this liquid (paraffin oil) to a degree which 
varies according to the quality from +16° to —18° C., paraffin is 
obtained which separates from the oil in the form of crystals which 
can be separated from the oil by filtration under pressure. The ap- 
pheation of refrigerating machines to this purpose makes possible 
the treatment at one time of large quantities of petroleum. As an 
example the works of Pardubitz in Bohemia are equipped with ma- 
chines of a capacity of a million frigories, and produce annually 
about four million (kilograms) of paraffin. 
The artificial silk called viscose is made by drawing through very 
fine openings a thick solution of cellulose obtained with alkaline or 
sulpho-alkaline solvents (caustic soda and carbon disulphide). To 
accomplish this successfully the solution must be-allowed to stand 
in vessels cooled artificially to +2° C. for a month or two before 
spinning. The solution is then sufficiently pure to be decanted and 
spun with success. 
IV. TRANSPORTATION WITH REFRIGERATION. 
The question of transportation of products under refrigerating 
conditions is one which has justly been a subject of careful considera- 
tion by transportation companies both on land and sea. 
The refrigerator cars or trains are of several types. 
(1) The refrigerator train, consisting of a group of cars, one of 
which has no capacity for storage, but contains a complete refrigera- 
