Cannon Making (CTP1)

Cannon-Making is an advance in Civilization: Call to Power.
==Summary==
Cannonmaking, the fifth Defensive War Advance, changes siege warfare forever. The Cannon adds an entirely new flavor to the long-ranged attack. The massive iron balls fired from the brass or iron barrels of the Cannon are far more destructive than the Archer's arrows.
== Great Library entry ==
The discovery of Gunpowder drove a massive investment in metallurgy as nations sought to develop more dependable and more accurate gun barrels. As often is the case, this research borrowed heavily from non-military fields. Turning to the reverberatory furnace (a coal furnace developed in the 17th century for glassmaking) to cast the iron, nations were able to make stronger, lighter iron cannons. These cannons replaced their bronze barreled predecessors, and artillery gained further prominence on the battlefield.