CADY AND MCFARLAND.| Composition of Natural Gas. 237 
these gases from mixtures and have made it possible to easily 
determine the presence and amount of at least the helium and 
neon in any gas. This has been done in the case of the present 
series of analyses, and the remarkable fact has been shown that 
helium is a constituent of every natural gas examined. Argon 
and neon have also been found in some of the gases, and it is 
probable that these also are universal constituents of natural 
gas. 
The methods of determining the amounts of these and of 
krypton and xenon are still in such a condition as to make them 
difficult of performance. 
Their importance in the gas lies not in any fuel value which 
they might have, because they are absolutely inert, so far as 
known, but rather in the utilization of the gas as a prolific 
source of these for experimental or other use. Already consid- 
erable quantities of helium have been extracted from Kansas 
gas and utilized in this way. 
HYDROGEN SULFID. 
This gas has been reported in a few analyses of American 
natural gas, particularly those made by Howard on Ohio and 
Indiana gases. It is a somewhat disagreeable-smelling sub- 
stance, and this fact usually makes its detection easy if it is 
present in any quantity. None of the Kansas gases have given 
this kind of evidence of its presence, and careful tests on sev- 
eral samples, by passing the gas through lead acetate solution, 
have shown none of it. 
OTHER CONSTITUENTS. 
Other substances which have sometimes been reported in 
gas analyses are ammonia and sulfur dioxid. The first has 
never been found in more than traces, while the second is prac- 
tically never a constituent of commercial gas. It is sometimes 
found in gases from spring waters, particularly in volcanic 
regions, and is a normal product of volcanic action in some 
places. 
From the above catalogue, it may be seen how few are the 
gases which enter into the mixture called natural gas, and this 
will be confirmed by a study of analyses. 
116. See section II of this chapter. 
