Note 271 — Chapter V · THE SECOND CHALCITIC AGE OF ALLOYS[242]—BRONZE, BRASS, ETC.: THE AXE AND THE SWORD.

Phosphor-bronze, for whose manufacture companies are now established in London and elsewhere, has the ordinary composition with the addition of red or amorphous phosphorus dropped upon the melted metal in the crucible. Berthier (Traité des Essais, ii. 410) states that a very small quantity of phosphorus renders copper extremely hard and suitable for cutting instruments. Percy (Metallurgy) found that copper will take up 11 per cent. of phosphorus; the metal, which assumes a grey tint, is quite homogeneous, and so hard that it can scarcely be touched by the file. The addition of phosphorus promotes the reduction of the oxides, and enables an exceedingly sound and durable casting to be made; but if it exceed ½ per cent. the metal becomes very brittle. Dr. Percy has described phosphor-silver, phosphor-lead, and phosphor-iron. The phosphorus is, according to some authorities, apt to volatilise with time. At present a new form of bronze, the antimonial, in proportions of 1–2 per cent., is coming into fashion: it is said to be malleable and ductile, and to resist torsion in a high degree. Another new bronze is the aluminium, whose price has been reduced from 1,000l. to 100l. per ton by Mr. Webster, of Hollywood, near Birmingham.