Without undertaking to affirm, we may obviously conjecture that this article has been inserted on the part of the United States from an overcaution to guard, nommement, by name, against a particular aggrievance, which they thought they could never be too well secured against; and that has happened which generally happens—­doubts have been produced by the too great number of words used to prevent doubt.

II.  The Court of France, however, understands this article as intended to introduce something to which the preceding articles had not reached, and not merely as an application of them to a particular case.  Their opinion seems to be founded on the general rule in the construction of instruments, to leave no words merely useless for which any rational meaning can be found.  They say that the reservation by the United States of a right to lay a duty equivalent to that of the 100 sols, reserved by France, would have been completely useless if they were left free by the preceding articles to lay a tonnage to any extent whatever; consequently, that the reservation of a part proves a relinquishment of the residue.

If some meaning, and such a one, is to be given to the last member of the article, some meaning, and a similar one, must be given to the corresponding member.  If the reservation by the United States of a right to lay an equivalent duty implies a relinquishment of their right to lay any other, the reservation by France of a right to continue the specified duty to which it is an equivalent must imply a relinquishment of the right on her part to lay or continue any other.  Equivalent reservations by both must imply equivalent restrictions on both.  The exact reciprocity stipulated in the preceding articles, and which pervades every part of the treaty, insures a counter right to each party for every right ceded to the other.

Let it be further considered that the duty called tonnage in the United States is in lieu of the duties for anchorage, for the support of buoys, beacons, and light-houses, to guide the mariner into harbor and along the coast, which are provided and supported at the expense of the United States, and for fees to measurers, weighers, gangers, etc., who are paid by the United States, for which articles, among many others (light-house money excepted), duties are paid by us in the ports of France under their specific names.  That Government has hitherto thought these duties consistent with the treaty, and consequently the same duties under a general instead of specific names, with us, must be equally consistent with it.  It is not the name, but the thing, which is essential.  If we have renounced the right to lay any port duties, they must be understood to have equally renounced that of either laying new or continuing the old.  If we ought to refund the port duties received from their vessels since the date of the act of Congress, they should refund the port duties they have received from our vessels since the date of the treaty, for nothing short of this is the reciprocity of the treaty.