Hero of Alexandria Biography


(Historic Lives: The Ancient World, Prehistory-476)

Article abstract: Egyptian scientist and inventor{$I[g]Egypt;Hero of Alexandria}{$I[g]Alexandria;Hero of Alexandria} Hero wrote about mechanical devices and is the most important ancient authority on them. Some of these were his own inventions, including a rudimentary steam engine and windmill. He also investigated mathematics, where his most noted contribution was a method for approximating square roots.

Early Life

Virtually nothing is known about the personal life of Hero (HEE-roh), also known as Heron, of Alexandria, other than the fact that an eclipse of the moon visible from Alexandria and mentioned in one of his books occurred in 62 c.e. Under the Roman Empire, Alexandria flourished somewhat less than it had under the Ptolemies, but the famous museum was still a center of research and learning where scientists and philosophers were active. Technology also continued to make amazing strides, so that Hero found an atmosphere conducive to his own theories and inventions. His writings show that he was an educated man, familiar with Greek, Latin, Egyptian, and even Mesopotamian sources, and reveal a wide-ranging mind unusual for his time. There is no indication that he worked for either a Roman patron or the Roman government.

Life’s Work

Hero’s greatest renown results from the fact that many of his writings on mechanics and mathematics are extant. The mechanical works include the two-volume Pneumatica (The Pneumatics of Hero of Alexandria, 1851), on devices operated by compressed air, steam, and water; Peri automatopoietikes (Automata, 1971), on contrivances to produce miraculous appearances in temples; the three-volume Mechanica, surviving in Arabic, on weight-moving machines; Dioptra (partial English translation, 1963), on instruments for sighting and other purposes; Catoptrica (surviving in Latin), on mirrors; and two artillery manuals, Belopoeïca (English translation, 1971) and Cheiroballistra (English translation, 1971), on different types of catapults. Missing are other works on weight-lifting machines (Baroulkos, which might be a name for part of Mechanica), water clocks, astrolabes, balances, and the construction of vaults.

Of his mathematical treatises, there exist the three-volume Metrica, on the measurement and division of surfaces and bodies, and Definitiones, on geometrical terms. There are other works, more or less heavily edited by later redactors, such as Geometrica, Stereometrica, and Peri metron (also known as Mensurae), all treatises on measurement, as well as Geodaesia and Geoponica or Liber geeponicus, on the measurement of land. A commentary on Euclid is represented by extensive quotations in the Arabic work of an-Nairīzī.

The contents of Hero’s mechanical works reveal the state of technological knowledge during the early Roman Empire, reflecting the heritage of the Hellenistic period and Ptolemaic Alexandria in particular. Later writers referred to him as “the mechanic” (ho mechanikos). In most cases, he gives the best or most complete description extant of ancient machines. In Mechanica, he gives attention to the simple machines—lever, pulley, wheel and axle, inclined plane, screw, and wedge—but he goes on to present others, there and in his other books, that are more complex.

Devices described by Hero include a machine for cutting screw threads on a wooden cylinder; a syringe; an apparatus for throwing water on a fire by hydraulic pressure, which is produced by a two-cylinder force pump (designed by the earlier Alexandrian mechanic, Ctesibius); and the odometer, for measuring distances by a wheeled vehicle. Of value to scholars, there was a pantograph for...

(The entire section is 1593 words.)