The composition of bell metal varies considerably, as may be seen below:
I.—(Standard.) Copper, 78 parts; tin, 22 parts; fused together and cast. The most sonorous of all the alloys of copper and tin. It is easily fusible, and has a fine compact grain, and a vitreous conchoidal and yellowish-red fracture. According to Klaproth, the finest-toned Indian gongs have this composition.
II.—(Founder’s Standard.) Copper, 77 parts; tin, 21 parts; antimony, 2 parts. Slightly paler and inferior to No. I.
III.—Copper, 80 parts; tin, 20 parts. Very deep-toned and sonorous. Used in China and India for the larger gongs, tam-tams, etc.
IV.—Copper, 78 to 80 parts; tin, 22 to 20 parts. Usual composition of Chinese cymbals, tam-tams, etc.
V.—Copper, 75 (= 3) parts; tin, 25 (= 1) part. Somewhat brittle. In fracture, semivitreous and bluish-red. Used for church and other large bells.
VI.—Copper, 80 parts; tin, 10 1/4 parts; zinc, 5 1/2 parts; lead, 4 1/4 parts. English bell metal, according to Thomson. Inferior to the last; the lead being apt to form isolated drops, to the injury of the uniformity of the alloy.
VII.—Copper, 68 parts; tin, 32 parts. Brittle; fracture conchoidal and ash-gray. Best proportions for house bells, hand bells, etc.; for which, however, 2 of copper and 1 of tin is commonly substituted by the founders.
VIII.—Copper, 72 parts; tin, 26 1/2 parts; iron, 1 1/2 parts. Used by the Paris houses for the bells of small clocks.
IX.—Copper, 72 parts; tin, 26 parts; zinc, 2 parts. Used, like the last, for very small bells.