CADY AND MCFARLAND.|] Composition of Natural Gas. 269 
53. Gas from coal-mine, Doranci colliery, near Scranton, Pa. 
Collected by J. T. Beard, principal of coal-mining division of 
International Correspondence Schools, December 31, 1907. 
Analyzed at Lawrence, Kan., January 8, 1908. Gas taken from 
drill-hole driven six feet into face of coal. Gas escapes from 
hole at rate of five feet per second. 
54. Natural gas from Pierre, S. Dak. Collected by Mr. 
Doane Robinson, secretary of the State Historical Society, 
Pierre, S. Dak. Sample had air in it. Only partial analysis 
made. 
DISCUSSION OF RESULTS. 
An inspection of table 27 shows that in all cases save one, the 
Los Angeles gas, helium was found, and it seems very probable 
that it might have been found in this also if a sufficiently large 
quantity of gas were taken for analysis. It will be noticed that 
gas was examined not only from the Kansas field and the ad- 
joining Oklahoma and Missouri fields, which are really con- 
tinuations of the former, but also representative samples from 
six other gas-fields at rather widely separated positions in the 
country—West Virginia, Ohio, Indiana, Louisiana, California 
and South Dakota, besides one gas from a Pennsylvania coal- 
mine. 
Since our work has been more particularly with the gases of 
Kansas we may discuss these at length. 
It is at once seen that the composition of these gases varies 
widely, frequently in places which are but a few miles apart. ° 
A case of this kind is found in the gases from Arkansas City 
and from Dexter, towns only about twenty miles apart. (See 
page 270.) The same phenomenon has been noticed with the 
oils of Kansas; oil from one side of a town is sometimes of very 
different composition and properties from that on the other 
side. This is said to be due to the fact that the porous sand- 
stone which carries the oil and gas is not laid down in continu- 
ous layers, but in lenticular masses of irregular size and dis- 
tribution. 
In general, the helium content increases with the nitrogen, 
although a direct proportionality does not appear to exist. Of 
course the percentage of both decreases as the percentage of 
total paraffin hydrocarbons increases, although the ratio of 
helium to nitrogen may increase. 
While there is such a wide variation in the composition of 
the different gases, there is a marked tendency toward regu- 
