266 ECONOMIC PRINCIPLES

out that the conception of free trade does not involve the
absence of all import duties. The spirit of the policy may
prevail even where many such duties exist. In some
circumstances, it may appear desirable to raise public
revenue by means of duties on imports, rather than to adopt
any other means. When this is done, the rule of “an equal
field to all” is not transgressed when the goods on which the
duties are imposed are not produced in the taxing country,
If the local circumstances render them incapable of being
produced there, or only at an extravagant expense, the rule
is obviously not transgressed, for no producer is put on a
better footing than others, If the goods be produced in the
country, and an excise duty, equivalent to that imposed on
imports, be levied on the domestic product, the same holds.
The former case is illustrated, in the English system, by
tea or coffee, the latter by spirits. These are, practically,
charged with consumption duties, levied as import duties, or
as import and excise duties combined.
The circumstances may render the levy of such excises
impracticable, and yet practical exigencies may demand that
revenue be raised by means of duties on imports, These
duties are, under the conditions considered, necessarily
protective whenever levied on goods similar to domestic
products. A revenue duty should be at, or below! the rate
which yields the greatest revenue obtainable: a protective
duty would preferably be made so much heavier than this
as to check the importation of the taxed goods, even though
revenue were seriously diminished as a result. If] then, the
rates charged, and the commodities selected for taxation,
are arranged so as to give the maximum of revenue with the
least difficulty possible, the general purpose of the tariff as
a revenue tariff will be clear, and its incidental protective
features, though they may be injurious, will be accepted as
due to fiscal exigencies rather than to a particular industrial
policy.
* Below, so as to permit of ready increase of revenue, in case of need.