It seems to me a convenient place to pause here a moment to inquire what is a law of nations, especially as it is a question very germane to our inquiry, and has been surrounded with a good deal of unnecessary confusion.
Laws of nations are of two kinds, according to the source from which they are derived: (1) Jura naturæ. (2) Those founded on Universus consensus gentium.
The first we may translate the law of common sense, the natural law founded on reason.
The second, the general agreement between the nations of the world.
It is sometimes considered that the second source is sufficient to constitute a law of nations; but it is evident that such a law might conflict with a still higher law, such as that of self-preservation, the first law of nature and of nations, and then it must yield to this higher law. A law merely founded on convention, however general the agreement, is a law of nations in an
