Copper             70
Manganese          30

Cast in ingots or in pigs it becomes an article of commerce which may be introduced in previously determined proportions into bronze, gun metal, bell metal, brass, etc.  It may also be used, as we have already mentioned, for the refining of copper according to Manhes’s process.

Tests made from this standpoint at the works of Mansfield have shown that the addition of 0.45 per cent. of cupro-manganese is sufficient to give tenacity to the copper, which, thus treated, will not contain more than 0.005 to 0.022 of oxygen, the excess passing off with the manganese into the scorias.

On the other hand, the addition of cupro-manganese is recommended, when it is desirable to cast thin pieces of the metal, such as tubes, caldrons, kitchen utensils, which formerly could only be obtained by beating and stamping.

The tenacity obtained for tubes of only three centimeters in diameter and 1.75 millimeters in thickness is such that they are able to withstand a pressure of 1,100 pounds to the square inch.

The manganese bronze, which we have previously referred to, and which is used by the White Brass Company of London, is an alloy of copper, with from one to ten per cent. of manganese; the highest qualities of resistance, ductility, tenacity, and durability are obtained with one to four per cent. of manganese, while with twelve per cent. the metal becomes too weak for industrial uses.

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

------+
| Manganese |         |           | Weight of   |            |
| bronze.   |  Copper.| Manganese.| fracture in | Elongation.|
|           |         |           | kilos per   |            |
|           |         |           | square mm.  |            |
+-----------+---------+-----------+-------------+-----------

-+
| A         |  96.00  |    4.00   |    19.00    |   14.60    |
| B         |  95.00  |    5.00   |    20.62    |   10.00    |
| C         |  94.00  |    6.00   |    20.80    |   14.60    |
| D         |  90.00  |   10.00   |    16.56    |    5.00    |
+-----------+---------+-----------+-------------+-----------

-+

The preceding table gives some of the experimental results obtained with the testing machine at Friedrich-Wilhelmshuette on the crude cast ingots; the resistance is increased, as with copper, by rolling or hammering.

The manganese German silver consists of

Copper................ 70.00
Manganese............. 15.00
Zinc.................. 15.00

But as this alloy often breaks in rolling, the preference is given to the following proportions: 

Copper................ 80.00
Manganese............. 15.00
Zinc..................  5.00

This results in a white, ductile metal, which is easily worked and susceptible of receiving a beautiful polish, like the alloys of nickel, which it may in time completely replace.