Artillery may be bought in Europe or constructed by the armories within your colonies. Artillery is very effective at attacking and defending colonies, and also at attacking fortified units and Indian settlements. However, when defending in unprotected terrain it is extremely vulnerable, and when attacking there it is ineffective. An artillery unit that is defeated in battle is damaged and loses some of its firepower; if defeated again, it is destroyed.
When purchasing Artillery in Europe, the first unit is 500 gold, and the price goes up 100 gold each time.