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.
History of tariffs in Australia
The pattern of tariffs and industry protection in Australia has favored manufacturers over the other two sectors producing tradeable goods: agriculture and mining. This pattern was established in the last quarter of the 19th century and it has persisted since then. The Brigden Committee Report regarded tariffs as a tax on exporters whose prices are fixed on world markets. “We may say, therefore, that the cost of tariff protection, falling ultimately on the export primary industries, falls chiefly on the owners of land, as such.”.