Melting
Aiton's Encyclopedia (1910)
or Fusion, passing from a solid to a liquid state. In theory, any solid may be turned into a liquid if heated sufficiently. Some solids, as ice, pass into a liquid abruptly; others, like iron, soften and yield before melting. Most substances increase slightly in volume as they melt, as may be noted by the fact that the unmelted portion lies at the bottom of the crucible. Cast iron , ice, and bismuth are exceptions. They float, showing that they shrink as they melt. As is well known, ice is lighter than water. Most metals melt at a higher temperature if subjected to increased pressure, but pressure assists the melting of ice and cast iron. Under ordinary or the same conditions of pressure, a substance always melts at the same temperature, and remains at that temperature during the process of melting. Ice, for instance, never fails to melt at 0 deg. C. or 32 deg. F., and, though thrown into boiling hot water, its temperature remains at 0 deg. C. or 32 deg. F. until it is entirely melted. TABLE OF MELTING POINTS--CENTIGRADE SCALE. Ice. . . . . 0 deg. Butter and lard. . . . . 33 deg. Mercury . . . . . 39 deg. Phosphorus . . . . . 44 deg. Potassium . . . . . 63 deg. Wax. . . . . 65 deg. Sodium. . . . . 95 deg. Sulphur. . . . . 110 deg. Tin . . . . . 230 deg. Bismuth . . . . . 262 deg. Lead . . . . . 326 deg. Zinc . . . . . 412 deg. Antimony . . . . . 432 deg. Aluminum . . . . . 600 deg. Bronze . . . . . 900 deg. Silver . . . . . 954 deg. Gold . . . . . 1045 deg. Copper . . . . . 1054 deg. Cast Iron . . . . . 1150 deg. Steel . . . . . 1350 deg. Wrought Iron . . . . . 1550 deg. Platinum . . . . . 1775 deg.
What Has Changed in the Last Century
The physics Aiton's set out in 1910 is still what is taught: melting at a fixed temperature under fixed pressure, latent heat holding ice at 0 °C until the last of it is gone, and the anomalous expansion of water on freezing. What has moved is precision. Modern values, tied to the international temperature scale adopted in 1990, put gold at 1064 °C rather than 1045, copper at 1085 rather than 1054, aluminium at 660 rather than 600, and mercury at minus 38.8 °C — the table's "39" has plainly lost its minus sign. Two qualifications would also be added now: not every solid simply melts on heating, since carbon dioxide sublimes and carbon needs enormous pressure to become liquid at all, and the old textbook claim that pressure-melting explains ice-skating is no longer accepted as the whole story.
Written for this edition, 2026.