258 University Geological Survey of Kansas. 
After the determination of carbon monoxid, a portion of the 
residue, usually about 20 ecc., was measured off, mixed with 
pure oxygen and air in such a manner as to give a proper ex- 
cess of oxygen, and exploded over mercury. The contraction 
in volume, and the amount of carbon dioxid produced, were 
determined in the usual manner, taking precautions to avoid, 
as much as possible, the error introduced by the absorption of 
carbon dioxid in the water produced by the explosion, which 
error may be considerable if haste is not used in the measure- 
ment of the volume after explosion. The residual oxygen was 
then determined by means of the phosphorus pipette in order to 
show both its amount and also that of the residual nitrogen. 
Frequent readings of barometer and thermometer enabled cor- 
rections to be made for changes in temperature and pressure. 
From the explosion data the quantities of methane and eth- 
ane were calculated, assuming that these were the only paraffin 
hydrocarbons present; an assumption which is not entirely 
warranted, because of the fact that it was found possible to 
condense higher-boiling hydrocarbons along with the methane 
in a bulb surrounded by liquid air. Some of these remained 
liquid up to ordinary temperatures and had an odor similar to 
that of light-boiling petroleum distillates. The quantity of 
this residue varied in the different gases. It has seemed prac- 
tically impossible to get at the amounts of these substances by 
explosion methods, and for the present the above assumption 
will be made. It seems probable, however, that they may be 
determined by the fractional distillation of the liquefied gas, 
and work along this line is being carried on in this laboratory. 
The formule used in the calculation were as follows: 
For Methane: 
(1) CH4=4 Oo — 7 CO 
(2) 3 CH4=4 Cont. — 5 COe 
(3) 4CH4=7 Cont. — 5 Oo 
For Ethane: 
(1) CoHg=4 CO2 — 2 Oo 
(2) CoH;=O — Cont. 
(3) 3 CoHg=4 COzg — 2 Cont. 
Each one involves two of the following factors: Contraction 
on explosion (Cont.), carbon dioxid (COz) formed during the 
explosion, and oxygen (Oz) used up in the explosion. 
A small error in the measurement of any of these quanti- 
ties is apt to produce large error in the calculated results. 
(See “General Discussion,” section IV, p. 280.) 
