contribution during the war in the ports of Mexico in possession of our
Army or Navy by conquest, with regulations for the ascertainment and
collection of such duties, together with the reasons which appear to me
to recommend their adoption.

It is clear that we must either adopt our own tariff or that of Mexico,
or establish a new system of duties. Our own tariff could not be
adopted, because the Mexican exports and imports are so different from
our own that different rates of duties are indispensable in order to
collect the largest revenue. Thus upon many articles produced in great
abundance here duties must be imposed at the lowest rate in order to
collect any revenue, whereas many of the same articles are not produced
in Mexico, or to a very inconsiderable extent, and would therefore bear
there a much higher duty for revenue. A great change is also rendered
necessary by the proposed exaction of duties on all imports to any
Mexican port in our possession from any other Mexican port occupied by
us in the same manner. This measure would largely increase the revenue
which we might collect. It is recommended, however, for reasons of
obvious safety, that this Mexican coastwise trade should be confined to
our own vessels, as well as the interior trade above any port of entry
in our possession, but that in all other respects the ports of Mexico
held by us should be freely opened at the rate of duties herein
recommended to the vessels and commerce of all the world. The _ad
valorem_ system of duties adopted by us, although by far the most just
and equitable, yet requires an appraisement to ascertain the actual
value of every article. This demands great mercantile skill, knowledge,
and experience, and therefore, for the want of skillful appraisers (a
class of officers wholly unknown in Mexico), could not at once be put
into successful operation there. If also, as proposed, these duties are
to be ascertained and collected as a military contribution through the