28 
BULLETIN 102, UNITED STATES NATIONAL MUSEUM. 
Transmission from the roots, trans— across, and mitto — to send, 
emphasizes the fundamental ideas of “to send through” and “to 
send ” and where interstate lines are involved, to “ send across ” such 
lines. The fundamental idea “to send” is especially relevant, be- 
cause the gas is always sent* through the line by virtue of its own 
expansive force, as explained on page 101, and never pulled through 
by anything ahead, while transportation from the roots, tram— 
across, and porto ^ to carry, suggests fundamentally transference 
only. That is, you transmit through, but transport over. Transmit, 
for “to send,” fixes the attention immediately on the intervening 
agency and relates to the service, while transport relates to the com- 
modity, although both imply delivery. 
WHY NATURAL GAS IS COMPRESSED. 
Natural gas is compressed merely to expedite transmission — -for 
the same reason that makes it necessary to compress cotton, hay, or 
straw, for shipment. The first feature is to contract the volume, and 
secondly, to secure enough pressure range between the intake and dis- 
charge of the transmission line to secure a large enough pressure 
drop to force the gas through the line. 
The broad public interest in an effective and continuous service 
and a future generation’s equity in a conserved future supply makes 
it the duty of the gas-producing company : 
1. To conserve the supply of gas in every wa}^ possible. Ity 
conservation is meant not merely saving, but using in the most effec- 
tive manner. This means that it is the duty of the gas. company — 
when it can be done without financial loss — to remove every foot of 
gas from the ground that can be obtained. 
2. Every appliance known to the art ought to be used to bring 
about the most economical mining of the gas, and most effective 
method of transmission and distribution. A normal characteristic 
of every gas field is that its rock pressure declines each year as the 
gas is removed from the ground, as shown in graphical form in 
figures 8 and 4. This means that as the fields grow older it is neces- 
sary for the gas company to increase the rapidly declining pressure 
by mechanical means. 
HOW NATURAL GAS IS COMPRESSED. 
This is accomplished by a compressor which is merely a mechanical 
device to squeeze the gas together into a small volume, thereby in- 
creasing its pressure. The specific effect of gas- compression is evi- 
dent from the following: If we take 1,000 cubic feet of gas at 4 
ounces gage pressure and increase the gage pressure to 300 pounds, 
the volume ’will be contracted to 46 cubic feet. 
