In Figure 12-4, Dx and Sx refer to the domestic demand and supply curves of commodity X, which Sf is the horizontal foreign supply curve of the nation’s imports (on the assumption that the nation is too small to affect the world price of commodity X ). If the nation imposes a $1 tariff on each unit of commodity X imported, the new foreign supply curve of imports to the nation shifts up to S’f. From the figure, we see that with the tariff (i.e., with S’f) Px=$4 for domestic consumers (compared with Px =$3 without the tariff), domestic consumers purchase AC’ = 500X (compared with AC=600x without the tariff), domestic producers produce AB’ = 300X (instead of AB=200X), and the government collects $200 in revenues ($1 per unit on each of the 200X imported).