What does impressmeant and tariff mean

Impressment refers to the act of taking men into a military or naval force without the person knowing and tariff are used to restrict trade because they cause the price of imported goods and services to increase (basically taxes).

president thomas jefferson commissioned the expedition shortly after the louisiana purchase in 1803 to explore and to map the newly acquired territory, to find a practical route across the western half of the continent, and to establish an american presence in this territory before britain and other european powers