Fusible Metal, an alloy which melts at a temperature below that of boiling water. It consists of a mixture of several metals, of which bismuth is the most important. The following are examples:
| Composition. | Melts at |
|---|---|
| 4 bismuth, 2 lead, 1 tin, and 1 cadmium | 60.5° C. (141° F.). |
| 5 bismuth, 3 lead, and 1 tin | 91.6° C. (197° F.). |
| 8 bismuth, 5 lead, and 3 tin | 94.5° C. (202° F.). |
Both on account of its melting at a low temperature and of its property of expanding as it cools, fusible metal is valuable for several purposes in the arts. It is used in stereotyping, in taking casts of medals and of woodcuts, and in testing the finish of dies. It has also been employed for making anatomical casts, and a peculiar kind of it was used for making safety-plugs for steam-boilers. For the latter purpose it melts when the pressure of the steam becomes dangerously high. It was found, however, that the alloy underwent some change, by being kept long heated to near its melting-point, which rendered it unsuitable.