was under the atmospheric pressure, there being a large enough opening to prevent any back pressure, the combustion of both gas and coal was not hurried.  It was found that the lower row of tubes could be plugged and the same amount of water could be evaporated with the coal; but with gas, by closing all the tubes—­on the end next the stack—­except enough to get rid of the products of combustion, when the pressure on the walls of the furnace was three ounces, and the fire forced to its best, it was found that very nearly the same results could be obtained.  Hence it was concluded that the most of the work was done on the shell of the boiler.”

In no other way can I give the members of the Iron and Steel Institute so much information in regard to this new fuel as by including in this paper a very able communication from the chief chemist at our Edgar Thomson Steel Works, Mr. S.A.  Ford, who is to-day the highest authority upon the subject: 

“So much has been claimed for natural gas as regards the superiority of its heating properties as compared with coal, that some analyses of this gas, together with calculations showing the comparison between its heating power and that of coal, may be of interest.  These calculations are, of course, theoretical in both cases, and it must not be imagined that the total amount of heat, either in a ton of coal or 1,000 cubic feet of natural gas, can ever be fully utilized.  In making these calculations I employed as a basis what in my estimation was a gas of an average chemical composition, as I have found that gas from the same well varies continually in its composition.  Thus, samples of gas from the same 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|