224 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1909. 
of the car completely from the outside air has been generally aban- 
doned. The ice-cooled cars now in use are usually provided with an 
arrangement which draws in air from the outside and sends it, after 
cooling it by contact with the ice, to renew the air in the car. The 
free space remaining for the disposition of the merchandise is about 
30 to 40 cubic feet, allowing the introduction of a load of from 6 to 10 
tons, according to the nature of the products. By an ice consumption 
of an average of 400 kilograms per day a temperature varying between 
8° and 4° C.is obtained. The degree of humidity is high, however. 
The cars cooled by evaporation of a liquid gas (in this case am- 
monia) carry on the outside two cylindrical tanks of quid ammonia. 
This fluid is sent by regulating cocks into coils placed at the two ends 
of the car on the inside. The ammonia evaporates and absorbs heat, 
the ammonia gas produced dissolving in water in a tank placed under 
the car. One car of this variety was experimented with in 1905 in 
the transportation of butter from Siberia. The cost of refrigeration 
‘for butter maintained at a temperature of from 4° to 5° C. was as 
high as 0.068 frane per kilogram of butter per day. 
In the ice-cooled cars of various types experimented with by the 
same Russian commission the total cost of refrigeration, including all 
expenses (ice consumption and charging, installation of ice houses, 
and operation of cars), amounted to 0.009 francs per kilogram of 
butter. 
As the short summary I have just made shows, the First Inter- 
national Congress of Refrigeration has examined with care most of 
the scientific and technical problems which exist in the refrigerating 
industry. If it has solved any of these problems it has indicated in 
the form of resolutions a very great number of others which up to 
the present have been only incompietely worked out. The next inter- 
national congress, which will be held in Vienna in 1910, will not be 
inferior to that at Paris, and will bring us, let it be hoped, in the 
scientific phase, to some accurate knowledge of the properties of bodies 
at low temperatures, and in the industrial phase to a uniformity of 
units of measure and methods of testing machines and insulating 
material. 
