well, but taken on different days, vary in nitrogen from 23 per cent. to
_nil_, carbonic acid from 2 per cent. to _nil_, oxygen from 4 per cent,
to 0.4 per cent., and so with all the component gases. Before giving the
theoretical heating power of 1,000 cubic feet of this gas I will note a
few analyses. The first four are of gas from the same well; samples
taken on the same day that they were analyzed. The two last are from two
different wells in the East Liberty district:

ANALYSES OF NATURAL GAS.

--------------------+--------+--------+--------+--------+--------+--------+
| 1 | 2 | 3 | 4 | 5 | 6 |
--------------------+--------+--------+--------+--------+--------+--------+
When tested.........|10-28-84|10-29-84|11-24-84|12-4-84 |10-18-84|10-25-84|
| per ct.| per ct.| per ct.| per ct.| per ct.| per ct.|
Carbonic acid ......| 0.8 | 0.6 | Nil. | 0.4 | Nil. | 0.30|
Carbonic oxide......| 1.0 | 0.8 | .58 | 0.4 | 1.0 | 0.30|
Oxygen... ... ......| 1.1 | 0.8 | .78 | 0.8 | 2.10| 1.20|
Olefiant gas .......| 0.7 | 0.8 | 0.98| 0.6 | 0.80| 0.6 |
Ethylic hydride ....| 3.6 | 5.5 | 7.92| 12.30 | 5.20| 4.8 |
Marsh gas ..........| 72.18| 65.25| 60.70| 49.58 | 57.85| 75.16|
Hydrogen ...........| 20.02| 26.16| 29.03| 35.92 | 9.64| 14.45|
Nitrogen ...........| Nil. | Nil. | Nil. | Nil. | 23.41| 2.89|
Heat units .........|728,746 |698,852 |627,170 |745,813 |592,380 |745,591 |
--------------------+--------+--------+--------+--------+--------+--------+

"We will now show how the natural gas compares with coal, weight for
weight, or, in other words, how many cubic feet of natural gas contain as
many heat units as a given weight of coal, say a ton. In order to
accomplish this end we will be obliged, as I have said before, to assume