────────────────────┬──────────────────────────┬────────┬────── Substance. │ Physical Condition. │ Deg. │ Deg. │ │ Cent. │ Fahr. ────────────────────┼──────────────────────────┼────────┼────── Water (ice) │ At Melting Point │ 0 │ 32 Water │ ” Boiling ” (760 mm.)│ 100 │ 212 Naphthalene │ ” ” ” ” │ 217·9 │ 424 Benzophenone │ ” ” ” ” │ 305·9 │ 582 Zinc │ ” Melting ” │ 419·4 │ 787 Antimony │ ” ” ” │ 630 │ 1166 Common Salt │ ” ” ” │ 801 │ 1474 Silver (in reducing │ │ │ atmosphere) │ ” ” ” │ 961 │ 1761 Gold │ ” ” ” │ 1063 │ 1945 Copper (in reducing │ │ │ atmosphere) │ ” ” ” │ 1083 │ 1982 ────────────────────┴──────────────────────────┴────────┴────── For higher temperatures the melting points of nickel (1452° C.) and palladium (1549° C.) are employed, but the accuracy in these cases is not so certain as with the substances named in the table. A useful point, intermediate between copper and nickel, has been established by E. Griffiths, and is obtained by heating nickel with an excess of graphite, when a well-defined eutectic is formed which freezes at 1330° C., or 2426° F.