Recent efforts to codify the international law of war have tended to differentiate more sharply between land warfare and naval warfare. But it is still frequently difficult to say where land warfare ends and naval warfare begins, and too little assistance is to be had from the few writers who have attempted to draw the line. The need of a clearly drawn line is evident when the capture of private property is being considered, for very different considerations apply in the two kinds of warfare. If a capture is governed by naval law, perplexing problems of prize court procedure may arise; but a seizure governed by land law is free from all necessity for prize court adjudication and confers a title which without more may be asserted in a neutral country.

With the victorious growth of Napoleon’s military power subsequent to the disastrous rupture in May, 1803, of the peace concluded at Amiens on March 27, 1802, the emperor determined to revive and develop certain conceptions already illustrated in decrees of the Directory and Consulate which had looked to the subversion of England through limitation or annihilation of its sea-borne commerce.

That the laws of nations with respect to the right of visit and search, and the right of capture were well defined and established in 1914 can not be doubted. The best proof that there were such laws in force is the fact that there was not in the sisterhood of nations a single enlightened state whose prize courts had not undertaken to interpret and administer them, and to award damages for their violation. The interpretations of these courts may have varied, just as the interpretations of statutory law vary among the municipal courts of the same state, but there were, nevertheless, such laws, and they were interpreted. Furthermore, it would appear that by the courts of Great Britain and the United States in particular, they were interpreted and administered with as high a degree of uniformity as the same law is ordinarily interpreted and administered by the courts of two or more different states of the American Union.

In a maritime war the formal announcements of national executives concerning principles of intended action possess an interest frequently transcending the occasion calling them into being since they may originate important modifications in the imprescriptible system of the law of nations and thus become touched with that universality of which the sea itself offers so constant and striking a suggestion. In the conflicts of the French revolution and the First Empire, as well as in the great war of our own day, we find produced on the part of the opposing governments a series of declarations (orders in council, arrêts) which have a permanent interest for the student of international law since they practically extend over the whole field of naval warfare and reach every aspect of belligerent action upon the high seas, while they may also become a cause oftentimes of strained relations between belligerent and neutral Powers arising through widely varying views touching the application of prize law to marine captures.

The course of the development and modification of exterritoriality in Siam is so little known that an account of it may not be without interest to students of international law.