Magnetism allows the building of frigates, the second-highest carrying capacity sea vessel.
It is a prerequisite of electricity.
| Prerequisite advances:|
| Magnetism (Civ1)|
| Needed for further advances:|
The force of attraction or repulsion between various substances, especially iron, is due to the motion of electric charges and is known as Magnetism. A Magnetic object normally has two poles, a north-seeking pole and a south-seeking pole, named because a freely floating Magnet orients itself in the Earth's Magnetic field along a north-south axis. Magnetism may have been discovered in China, but its important application in the mariner's compass occurred in 12th Century Europe. Later work with Magnetism was important in the discovery of Physics and Electricity.