piracies and felonies extends no further than to the establishment of courts for the trial of these offenses. The definition of piracies might, perhaps, without inconveniency, be left to the law of nations; though a legislative definition of them is found in most municipal codes. A definition of felonies on the high seas is evidently requisite. Felony is a term of loose signification, even in the common law of England; and of various import in the statute law of that kingdom. But neither the common nor the statute law of that, or of any other nation, ought to be a standard for the proceedings of this, unless previously made its own by legislative adoption. The meaning of the term, as defined in the codes of the several states, would be as impracticable as the former would be a dishonorable and illegitimate guide. It is not precisely the same in any two of the states; and varies in each with every revision of its criminal laws. For the sake of certainty and uniformity, therefore, the power of defining felonies in this case was in every respect necessary and proper.
The regulation of foreign commerce, having fallen within several views which