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that observe it, with respect to each other. Whence it appears, that it is only binding to tliose natio'ns that have adopted it, and that is not universal, any more than conventional laws. It must be here also observed of this customary law, that the particulars relating to it, do not belong to a systematic treatise on the law of nations, but that we ought to confine ourselves to the giving a general theory of it; that is, to the rules which here ought to be observed, as well with re- spect to its effects, as in relation to the matter itself: and in this last respect, these rules will serve to distin- guish the lawful and innocent customs, from those that are unjust and illegal!
' When a custom is generally established, either be- t^veen all the polite nations in the world, or only be- tween those of a certain continent, as of Europe, for example; or those who have a more frequent corres- pondence; if that custom is in its own nature indifferent and much more, if it be a wise and useful one, it ought to be obligatory on all those nations who are considered as having given their consent to it. And they are bound to observe it, with respect to each other, while they have not expressly declared that they will not adhere to it. But if that custom contains any thing unjust or illegal, it is of no force; and every nation is under an obligation to abandon it, nothing being able to oblige or permit a nation to violate a natural law.
' These three kinds of the law of nations, voluntary, conventional, and customary, together, compose the positive law of nations. For they all proceed from the volition of nations; the voluntary law, from their pre- sumed consent: the conventional laiv, from an express consent; and the customary lata, from a tacit consent: and as there can be no other manner of deducing any