Tools & manufacturing · c. 300 BCE

Gear train

Toothed wheels trade speed for torque and count rotations.

Greek engineers such as Ctesibius used gears in the 3rd century BCE, and the Antikythera mechanism of about 100 BCE contains over 30 of them. Gearing drives mills, clocks and nearly every machine since.

See it in the living tree Wikipedia

Arcs above join it to what it stood on, arcs below to what it led to. The bar places this stretch on the tree's whole timeline.

What it built on 2

Euclid's Elements 300 BCE
The wheel 3500 BCE

What it led to 1

Mechanical clock 1280