Government. If Congress levy a duty for revenue of 1 per cent on a given
article, it will produce a given amount of money to the Treasury and
will incidentally and necessarily afford protection or advantage to the
amount of 1 per cent to the home manufacturer of a similar or like
article over the importer. If the duty be raised to 10 per cent, it will
produce a greater amount of money and afford greater protection. If it
be still raised to 20, 25, or 30 per cent, and if as it is raised the
revenue derived from it is found to be increased, the protection or
advantage will also be increased; but if it be raised to 31 per cent,
and it is found that the revenue produced at that rate is less than at
30 per cent, it ceases to be a revenue duty. The precise point in the
ascending scale of duties at which it is ascertained from experience
that the revenue is greatest is the maximum rate of duty which can be
laid for the _bona fide_ purpose of collecting money for the support of
Government. To raise the duties higher than that point, and thereby
diminish the amount collected, is to levy them for protection merely,
and not for revenue. As long, then, as Congress may gradually increase
the rate of duty on a given article, and the revenue is increased by
such increase of duty, they are within the revenue standard. When they
go beyond that point, and as they increase the duties, the revenue is
diminished or destroyed; the act ceases to have for its object the
raising of money to support Government, but is for protection merely. It
does not follow that Congress should levy the highest duty on all
articles of import which they will bear within the revenue standard, for
such rates would probably produce a much larger amount than the
economical administration of the Government would require. Nor does it
follow that the duties on all articles should be at the same or a
horizontal rate. Some articles will bear a much higher revenue duty than
others. Below the maximum of the revenue standard Congress may and ought
to discriminate in the rates imposed, taking care so to adjust them on