But this admission that the law of nature does not preclude appropriation of a relatively small part of the sea by the neighbouring state, he qualifies in a general way by saying that there are many things tolerated by the law of nature which the law of nations, by common consent, might prohibit; and where this law of nations was in force and is not repealed by common consent, the most inconsiderable part of the sea, although almost enclosed by the shores, can never be the property of a particular people. And in places where the law of nations was not received, or was afterwards abolished, it does not follow that the people merely because they possess the lands also possess the sea enclosed by them; the taking possession must be made by an overt act, and signified and made known. And if the possession thus gained by the right of prior occupation is afterwards abandoned, the sea returns to its original nature--namely, to the common use of mankind. Further, he who possesses any part of the sea cannot lawfully hinder unarmed ships, giving no room to apprehend danger, from sailing there, in the same way that he cannot justly prohibit innocent passage through his lands. Grotius goes on to explain that it is more easy to take possession of the jurisdiction (_imperium_) alone over part of the sea than of the right of property, and that it is not contradicted by the law of nations; and he points to a number of instances among the ancients.[627] He admits that sovereignty or jurisdiction may be acquired on the sea either in regard to persons or in regard to territory (_ratione personarum et ratione territorii_),--in regard to persons, as when a fleet, which is a maritime army, is maintained in any part of the sea; in regard to territory, as when those who sail along the coasts may be compelled from the land, as if they were actually on the land.[628] The latter statement of Grotius contains the germ of the idea subsequently adopted by almost all the writers on international law, that the extent of the adjoining sea over which the neighbouring state is entitled to exercise dominion is limited by the range of guns from the land. Grotius does not mention the means by which compulsion was to be made effective, but there is little or no doubt of what was in his mind.[629] It remained for Bynkershoek, at the beginning of the next century, to give the doctrine precise expression.