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.
German tariff of 1879
The tariff imposed moderate import duties on grain and raised the duties on livestock products. Wheat, rye and oats were subject to a duty of 1 mark per 100kg; on barley and maize 50 pfennigs; on flour 2 marks; on meat 12 marks; on oxen 20 marks; sheep 1 mark; pigs 25 marks. Raw materials for industry such as cotton, flax, hemp, wool and coal were admitted duty free. The duty on pig iron was 1 mark; on semi-manufactured goods made from iron and steel it ranged from 2 to 2.5 marks; for other iron and steel goods the duty ranged from 7.5 to 15 marks. On machinery it was 3 to 8 marks; for yarns and textiles the rates were 15 to 30 per cent. "ad valorem".