Mangane-sian iron is mixed with copper, melted in a reverberatory furnace, and run into pigs. An alloy capable of being rolled is made by melting this together with zinc and copper. For a bronze capable of being forged, protoxide of manganese and protoxide of iron, together with sufficient coal-dust to reduce the two oxides, are added to copper. After melting, the product is similar to aluminium bronze. (Л. Soc. Chem. Ind. i. 322).

Parson's manganese bronze is a member of that class of alloys in which copper forms the base and is alloyed with zinc and tin in various proportions, forming the different qualities of bronze, brass, yellow, and muntz metal, with addition of a proportion of spiegel-eisen, ferro-manganese, or other forms of carburet of iron, combined with a sufficient quantity of manganese, by which addition these alloys are rendered more homogeneous, closer in texture, harder, and stronger.

The alloys composed as above are very numerous, and have been given a variety of names, according to the proportions in which the metals composing them are combined; but to explain the best means of putting Parson's process into practice, these alloys may be classified under 3 heads: (1) Those composed of copper and tin (gun-metal); (2) copper, tin, and zinc (bronze); (3), copper and zinc (brass).

To obtain the best effects, the ferro-manganese to be used in the gun-metal alloys should be richer in manganese than that for the brass, while that for the bronze may be between the two, and regulated as conveniently as can be by the proportions of tin and zinc employed: that is to say, if little zinc is used in the bronze alloy, the ferro-manganese employed may be nearly as rich in manganese as in the gun-metal alloys; while if the zinc predominates, the ferro-manganese employed may be a trifle richer in manganese than that used in the brass alloys; and if the zinc and tin are about equal, the quantity of manganese contained in the ferro-manganese may be between that used for the gun-metal and that used for brass alloys. The ferro-manganese used to mix with the gun-metal alloys should contain 10 to 40 per cent. of metallic manganese, while that used to mix with the brass alloys should contain about 5 to 20 per cent.; and that used for the bronze alloys should be between the two, according to the proportions of tin and zinc employed.

In selecting the ferro-manganese to be used, it should contain as little silicon as possible; when spiegel-eisen can be obtained of the best quality, containing but a minute quantity of silicon, and 5 to 10 per cent. of manganese, it will be suitable to mix with the brass alloys, and it may even be used with the gun-metal alloys; but it will be found advantageous to apply for both, as well as the bronze, a ferro-manganese made as follows :-Procure ferro-manganese (as now manufactured for and used in steel-works) rich in metallic manganese, containing 50 to 60 or even 70 per cent.; melt this in a crucible under powdered charcoal, along with the requisite proportion of the purest wrought-iron scrap, to bring down the quantity of metallic manganese to any of the proportions before named. Supposing it is desired to employ a ferro-manganese, to mix with any of the before-named alloys, containing 20 per cent. of manganese, and a ferro-manganese, containing 60 per cent. of metallic manganese and say 1 per cent. of silicon, is melted with wrought-iron scrap in the proportion of 100 of ferro-manganese to 200 of wrought-iron scrap, a ferro-manganese containing the desired quantity of metallic manganese (20 per cent) will be obtained, containing only 1/3 per cent. of silicon instead of 1 per cent., and so on for any other proportions required; not only this, but a still further portion of the silicon is eliminated, and the metal is refined by this second melting in a crucible as described.

The quantity of ferro-manganese to be employed will vary both with the nature of the alloy and with the quality required in each particular alloy, and this will also to a certain extent have to be regulated by the quality of the copper, tin, and zinc employed. The purer these metals, the larger may be the quantity of ferro-manganese employed, and therefore no precise quantities can be specified; but generally, for ordinary gun-metal (composed of about 90 per cent. copper and 10 per cent. tin), 1/2 to 1 1/2 per cent. ferro-manganese may be added, containing say 20 per cent. metallic manganese; and as the tin is increased, the ferro-manganese should contain more manganese and less iron.

The quantity of ferro-manganese employed should be regulated according to the purposes for which the alloy is intended to be used; generally the effect produced is with the smaller quantities named to increase the strength of the alloy and the hardness slightly; and as the quantity of ferro-manganese is increased, the hardness is also increased, but at the same time the alloy becomes more brittle. A similar effect is produced by the addition of the ferro-manganese to the brass and bronze alloys. With the brass alloys, 1/2 to 5 per cent. of the ferro-manganese may be employed with advantage for general purposes; and for the bronze alloys, any proportions between those for gun-metal and brass alloys may be advantageously used, these proportions being adjusted according to the quantities of tin and zinc used : that is to say, the more tin used, the less should be the quantity of ferro-manganese.

In practice, the copper should be first melted in a crucible in the ordinary manner, and the spiegel-eisen or ferro-manganese, either with or without the addition of wrought-iron scrap, should at the same time be melted in a separate smaller furnace, capable of generating a high temperature, in a plumbago (graphite) crucible, under powdered charcoal; when it is completely fused, the copper also fused and at a boiling heat, the ferro-manganese should be poured into the copper, and the two well mixed together by stirring with an iron rod previously made red hot; the tin, zinc, or both should then be added in the usual way, and in the requisite proportions according to the kind of alloy it is required to produce. After the tin and zinc are added, the metal should be again well stirred with a red-hot rod, and skimmed; it may then either be poured into ingot moulds for future use, or it can at once be cast into moulds to produce any articles required.