60 ce

Energy

Heron of Alexandria builds a toy, later called an aeolipile, that uses jets of steam to turn a kettle. As water in the kettle is heated, the steam expands through vents that make the kettle rotate on an axle. There is apparently no idea of putting the device to practical use. See also 600 ce Energy. (See essay.)

Heron describes his invention of a lamp in which a column of saltwater supplies pressure to raise the level of oil into the wick. See also 250 bce Energy; 77 ce Energy.

Heron describes experiments with air, including the expansion of air caused by heat. He also writes books about simple machines and about light and mirrors.

Cleomedes [b. first century ce, possibly in Lysimachia, Greece, d. first century ce] calls attention to some of the elementary properties of refraction, such as the bending of a ray of light toward the perpendicular when it passes from a less dense to a more dense medium. There is some evidence that Archimedes and Euclid, both much earlier, may have known that refraction causes a coin in an opaque vase that is just below the line of sight over the rim to become visible when water is poured into the vase. Certainly Cleomedes knew this effect because he correctly notes that the same effect causes the Sun to be visible shortly before it actually reaches the line of sight over the horizon. See also 140 ce Physics.

Heron describes (and perhaps invents) a device for cutting screws with female threads. Male screw threads still have to be cut by hand. Some of Heron's other devices, not necessarily invented by him, include levels, worm gears, check and float valves (as in flush toilets), a toy windmill, and a force pump and nozzle for use in fighting fires. See also 300 bce Tools.

Nero [b. Antium, December 15, 37 ce, d. Rome, June 9, 68] starts to build a canal across the Isthmus of Corinth, a project contemplated at least as early as 600 bce, but his increasing political difficulties cause him to abandon it. See also 640 bce Transportation; 1893 ce Transportation.