3.  On the production of slag rich in bases.

These different conditions may be obtained with but slight variations at the different works, but the condition of a high temperature is one of the most important considerations, not only for the alloys of manganese, but equally as well for the alloys of iron, manganese, silicium, those of chromium, of tungsten, etc.  It is also necessary to study the effects produced either in the crucible or in the blast furnace, and to examine the ores which for a long while have been regarded as not reducible.

The works of Terre Noire especially made at the same time, in the blast furnace, ferro-silicon with manganese, alloys which are daily becoming more important for the manufacture of steels tempered soft and half soft without blowing.

These alloys, rich in silicon, present the peculiarity of being poor in carbon, the amount of this latter element varying with the proportions of manganese.  In addition to the alloys used in the iron and steel industry, we shall proceed to relate the recent progress obtained in the metallurgy of other materials (especially copper) by the use of cupro-manganese: 

+---+---------+-------+---------+---------+------+-----

-------------------------
|   |   Mn.   |   C.  |    Si.  |    S.   |  P.  |
|   |per cent.|       |         |         |      |
+---+---------+-------+---------+---------+------+
| A | 18 to 20| 2 to 3| 10 to 12| Traces  |      |Extra Quality for soft metals.
| B | 15 to 18| 3.00  | 10 to 8 | scarcely|About |} Medium Quality
| C | 15 to 10| 3.25  |  8 to 6 | percep- |0.100.|}
| D |  5 to 10| 3.50  |  4 to 6 | tible.  |      |Ordinary for hard metals.
+---+---------+-------+---------+---------+------+----------

--------------------

The first alloys of manganese and copper were made in 1848, by Von Gersdorff; soon after Prof.  Schroetter of Vienna made compounds containing 18 or 20 per cent. of manganese by reducing in a crucible the oxides of copper and manganese mixed with wood charcoal and exposing to a high heat.

These alloys were quite ductile, very hard, very tenacious, and capable of receiving a beautiful polish; their color varies from white to rose color, according to the respective proportions of the two bodies; they are particularly interesting on account of the results which were obtained by adding them to certain metallic fusions.

It is well known that in the fining of copper by oxidation there is left in the fined metal the suboxide of copper, which must then be removed by the refining process, using carbon to reduce the copper to its metallic state.  M. Manhes, taking advantage of the greater affinity of manganese for oxygen, found that if this last element was introduced into the bath of copper during the operation of refining, the copper suboxide would be reduced and the copper obtained in its metallic condition.  For this purpose during these last years real cupro-manganese has been prepared, occupying the same position to copper as the spiegel or the ferro-manganese does toward the manufacture of steel.  M. Manhes used these same alloys for the fusion of bronze and brass, and recommended the following proportions: