Dakota Datebook: Perpetual motion machine

For many years, humankind has quested for a machine of perpetual motion, something mechanized that would not stop moving. The first documented attempt comes from the Indian author Bhaskara around 1159. The machine was a wheel with containers of mercury around its rim, which was supposed to always maintain weight on one side as it spun, and thus keep moving.

Many other attempts would follow, some t...