80 BULLETIN 102, UNITED STATES NATIONAL MUSEUM. 
sary to do this would be so great as to make the plan prohibitive from 
a financial viewpoint. That is, the gas compression method is the 
economical way of handling the problem. The natural gas com- 
pressor performs a similar function to the step-up transformer for 
an electrical transmission line. 
NO HEAT LOSS IN NATURAL GAS COMPRESSION. 
Contrary to a widespread popular opinion, the compression of 
natural gas does not decrease its heating value. While a certain 
amount of gas is used to drive the compressors, this does not in any 
way affect the heating value of the gas passing through the com- 
pressors. On account of the mechanical work performed on the 
gas as it flows through the compressors the gas becomes quite warm, 
and to protect the rubbers in the main lines, is cooled just beyond 
the compressor discharge before it goes into the main line transmis- 
sion system. This, however, pertains merely to the temperature 
of the gas itself, and in no way affects its heating value. 
NOT FEASIBLE TO MAKE NATURAL GAS MAIN LINES COMMON CARRIERS. 
The natural gas main lines form the connecting link between the 
mining operations in the natural gas field and the public utility serv- 
ice in the city distributing plants. A number of attempts have been 
made by large consumers, owning natural gas in the field, to have 
the main transmission lines made common carriers so that they could 
be compelled to haul the large consumer’s gas to market. The con- 
verting of main lines into common carriers is not only not feasible 
from an operating viewpoint, but the idea could be based only on dis- 
tinctly local and selfish interests, and would ignore entirely the do- 
mestic consumers’ interest. That is, this plan would greatly injure 
service to the oyer 2,000,000 domestic natural gas consumers in the 
United States, because it is not generally appreciated that : 
1. There is a clear distinction between the duties of a common 
carrier or railroad, and the duties of a public utility. 
(a) The terms “railroad,” “common carrier,” and “public util- 
ity” are frequently confused. A railroad is a common carrier that 
undertakes for hire to transport persons or goods, or both, from place 
to place, for all persons indifferently. The fundamental duty of a 
railroad or common carrier being indifference as to who shall be 
served, and an equal readiness to serve all w-ho apply in the order 
of their application. On the other hand a property becomes a pub- 
lic utility only when dedicated to a public use. 
(b) Even though legislative enactments would be passed declaring 
natural gas lines public transportation agencies — that is, common 
carriers — they could not be enforced because such legislation would 
be in direct conflict with well-known economic and engineering 
