III. PHYSICS AND CHEMISTRY
By Professor Lawrence J. Henderson
THE history of physical science in the ancient world is marked by few notable results. The monochord, earliest of scientific apparatus, led to the discovery of the elements of harmony; geometrical optics in its simplest form was developed; Hero of Alexandria and others familiarized themselves with some of the phenomena of steam and air pressure; even Aristotle, whose influence in this department was on the whole so harmful during two millenniums, possessed much curious and interesting information. But, apart from the great work of Archimedes in mechanics, there is little that bears the imprint of genius in the physics and chemistry of antiquity. Most of the knowledge of the time was no better than a collection of rules of the various trades, such as dyeing, for instance.
THE ACHIEVEMENTS OF ARCHIMEDES
Archimedes established the science of statics. He discovered the law of the lever, that unequal weights are in equilibrium when their distances (from the fulcrum) are inversely proportional to their weights; he developed the idea of center of gravity, and discovered rules concerning it; and he discovered the laws of floating and immersed bodies, including the so-called principle of Archimedes, which enabled him, as the story goes, by weighing Hiero's crown in air and then in water, to detect that the goldsmith had debased the metal. This work of Archimedes, together with his remarkable mathematical feats, marks him as one of the mightiest of human intellects, fully worthy of a place among the greatest of the Greeks.
But, in spite of Archimedes, it was in fragmentary and disjointed form that the physical science of antiquity was transmitted without important change through the Middle Ages to the Modern
