Tariff
A tariff is called an optimal tariff if it's set to maximize the welfare of the country imposing the tariff. It is a tariff derived by the intersection between the "trade indifference curve" of that country and the offer curve of another country. In this case, the welfare of the other country grows worse simultaneously, thus the policy is a kind of "beggar thy neighbor policy". If the offer curve of the other country is a line through the origin point, the original country is in the "condition of a small country", so any tariff worsens the welfare of the original country.
Tariff of 1883
President Chester A. Arthur appointed a commission in May 1882 to recommend how much tariff rates should be reduced. The issue was controversial during the last three decades of the nineteenth century, making tariff revision a daunting task. Different constituents argued for opposite measures, often wanting to maintain tariffs on some items while reducing them on others. Support or opposition to tariffs often broke down along regional lines.