Nat'l Spirit (National Spirit) are points awarded after a promotion - completing a factory i.e. age 4/4 - or unlocking all the weapons within a given age. These points are spent in the "Buy" menu. They are used to increase revenue gains from specific sales of weapons manufactured with specific resources; e.g. increasing Copper's percentage (30% per gain) increases the value of a Blunderbuss (1.0 = 75, 1.3 = 97.5 . . .)