PRODUCTION OF LOW TEMPERATURES, AND 
REFRIGERATION. 
By L. MaARcHIS. 
(Translated by permission from the Revue générale des Sciences, pures et 
appliquées, Paris, 20th year, No. 5, March 15, 1909.) 
The first International Congress of Refr'gerative Industries, held 
at Paris October 5-12, 1908, was remarkable for the number and im- 
portance of the papers submitted by the men of science and engi- 
neers who responded to the call of the organization committee. 
The congress was divided into six sections as follows: 
First section. Low temperatures and their general effects. 
Second section. Refrigerating media. 
Third and fourth sections. Application of refrigeration to food 
and in various other industries. 
Fifth section. Application of refr:geration in commerce and trans- 
portation. 
Sixth section. Legislation. 
In this article we do not intend to summarize the memoirs and 
communications presented, but rather to give a general view of the 
congress that brought together men of scicnce, engineers, biologists, 
legislators, and men from the business world. 
I. LIQUID AIR AND THE PROPERTIES OF BODIES AT LOW TEMPERATURES. 
The first section considered principally the production of liquid 
air and the preparation, with this as a starting point, of oxygen 
and nitrogen in a commercial way. 
It is well known that air, like all gases, is brought into a lquid 
condition by the combined effect of lowering its temperature and 
expanding it sufficiently. In carrying out this process, gaseous air 
cooled to a low temperature is expanded suddenly from a pressure 
p, to a lower pressure p,. Part of it goes over into a liquid state, and 
the other part, gaseous and very cold, is led into an economizer, where 
it cools down the air that is being compressed to the pressure p, for 
the first time. 
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