square inch.

The air for producing the carbon monoxide (CO) gas was used at the
temperature of the atmosphere. As near as possible, the same conditions
were obtained in each experiment, and the equivalent weight of air was
sent through the carbon to generate the same weight of CO as that
generated when steam was used for the production of water gas.

[Illustration]

_First Experiment, Steam (per se)_.--Both tubes, A and B, were filled
with ore broken to the size of nuts. The tube, A, was heated to about
2,000 deg. Fahr., the upper one to about 1,500 deg.

NOTE.--In this experiment, part of the steam was dissociated in passing
through the turned-up end of the steam supply pipe, which became very
hot, and the steam would form with the iron the magnetic oxide
(Fe_{3}O_{4}). The reduction would doubtless be due to this
dissociation. The pieces of ore found on lowest end of the tube, A, were
dark colored and semi-fused; part of one of these pieces was crushed
fine, and tested; see column I. The remainder of these black pieces was
mixed with the rest of the ore contained in tube, A, and ground and
tested; see column II. The ore in upper tube was all broken up together
and tested; see column III. When finely crushed, the color of No. I. was
bluish black; No. II., a shade darker red; No. III., a little darker
than the natural color of the ore. The analyses gave:

-----------------------------+---------+---------+---------
| I. | II. | III.
+---------+---------+---------
|per cent.|per cent.|per cent.
Ferric oxide (Fe_{2}O_{3}). | 68.55 | 76.47 | 84.81
Ferrous oxide (FeO). | 16.20 | 9.50 | 1.50
+---------+---------+---------
Total. | 84.75 | 85.97 | 86.31
+---------+---------+---------
Calculated: | | |
Ferric oxide (Fe_{2}O_{3}). | 32.55 | 55.36 | 81.47
Magnetic oxide (Fe_{3}O_{4}).| 52.20 | 30.61 | 4.84
Ferrous oxide (FeO). | | |
+---------+---------+---------
Total. | 84.75 | 85.97 | 86.31
+---------+---------+---------
Percentage of total
oxygen reduced. | 6.93 | 4.02 | 1.07
Metallic iron. | 60.59 | 60.92 | 60.54
-----------