Brass, the most common and useful of the alloys, is a combination of copper and zinc in varying proportions.

High brass consists of copper 65 per cent, and zinc 35 per cent. It is called high brass because its percentage of zinc is high. This is the best brass for etching.

Low brass contains 85 per cent of copper, and 15 per cent of zinc.

Tough brass consists of copper 55 per cent, zinc 44 per cent, tin one-half of one per cent, aluminum one-half of one per cent.

Reel brass contains copper 85 per cent, tin 6 per cent, zinc 5 per cent, lead 4 per cent.

Yellow brass contains copper 67 per cent, zinc 31 per cent, lead 2 per cent.

Bearing brass, used especially for bearings on machinery, is a very hard alloy composed of copper 82 per cent, tin 14 per cent, zinc 4 per cent.

The standard automobile bearing alloy used by practically all of the prominent manufacturers is composed of copper 80 per cent, tin 10 per cent, lead 10 per cent.

The last two alloys given, altho they are called brass, are in reality bronze, the distinction being that in alloys of copper where the secondary metal is zinc, the alloy is known as brass. The alloy in which the secondary metal is tin is known as bronze.

Bronze bells are made of copper 75 per cent, tin 25 per cent.

Phosphor bronze, used extensively in boat building, is composed of copper 80 per cent, tin 15 per cent, zinc 5 per cent. When it is being melted a flux of phosphorus is used.

Monument bronze is composed of copper 87 per cent, tin 7 per cent, lead 3 per cent, zinc 3 per cent.