The second is, that all nations being equal, all have an equal right to the uninterrupted use of the unappropriated parts of the ocean for their navigation. In places where no local authority exists, where the subjects of all states meet upon a footing of entire equality and independence, no one state, or any of its subjects, has a right to assume or exercise authority over the subjects of another. In closing the preface to the _Mare Clausum_, Selden used language, which the undersigned quotes, albeit in an inverse sense, as a fit ending to this subject: “Other passages there are everywhere of the same kind. But I enlarge myself too much in a thing so manifest. Therefore I forbear to light a candle to the sun. Farewell reader.” JAMES BROWN SCOTT, _Director of the Division of_ _International Law_. WASHINGTON, D. C., _February 28, 1916_. TRANSLATOR’S PREFACE _The Latin Text_ The Latin Text is based upon the Elzevir edition of 1633, the modifications being only such as to bring the Latin into conformity with the present day Teubner and Oxford texts. References in the notes to classic authors are given in unabbreviated form, following in other respects the Thesaurus Linguae Latinae Index. Citations to the Civil Law are given in the modern notation, which is followed, in parentheses, by the older method of reference. The text used is that of Mommsen, Krueger, Schoell et Kroll. The Canon Law is cited from the Friedberg edition of 1879-81. The abbreviations used are explained below. _The Translation_ The translator wishes to make due acknowledgment for the passages from classic writers quoted from standard translations, to which references are also made in the notes. He has also consulted the French translation of Grotius by A. Guichon de Grandpont (1845). But his chief acknowledgment is to his colleague and friend, Professor Kirby Flower Smith of The Johns Hopkins University, to whom he read the translation, and who gave him the benefit of his knowledge of Latin and his taste in English, in a number of troublesome passages. Many niceties of the translation belong to Professor Smith, but mistakes in interpretation belong to the translator alone.