BOOK REVIEWS 739 rivers," i. e., those which form the national boundaries between states or flow through more than one state. The demands created by the growth of inter- national shipping had come into irreconcilable conflict with the mediaeval and feudal theory of the ownership of rivers, — a particularistic theory which made each state the uncontrolled owner of that portion of the river which lay within its boundaries. From such a theory came heavy local tolls and harassing regu- lations, so excessive and intolerable that either the theory must be modified or the rivers cease to be used as international highways. In a famous article (Art. 109) the diplomats of Vienna laid it down that the navigation of such international rivers "along their whole course, from the point where each of them becomes navigable, to its mouth, shall be entirely free, and shall not, as far as commerce is concerned, be prohibited to anyone." Since that day for a century there has been a conflict between what might be called the "states' rights" school, contending that the riparian states may together exclude from river navigation whom they will and make such com- mon regulations as they please, and the "internationalists' school," which maintains that international rivers shall be free and open to the ships of all nations upon equal and reasonable terms. The slow trend of opinion seems to have been in favor of the latter, if we may judge from the various conventions entered into during the last century. Whether or no we have yet reached a point where it can be said that in the absence of convention international rivers are legally open to the flags of all nations, the diplomats at Versailles can best decide. Certain it is that the problem of international rivers must be considered by them; "in the countries whose fate will have particularly to be decided after this war, questions like those of the Danube, of the PoUsh rivers, of the Rhine, of the Scheldt, etc., will call for particular attention" (p. 28). In order to bring together and review the mass of facts and docimients con- nected with the regulation and administration of international rivers during the past century, Mr. Kaeckenbeeck, a gifted young Belgian who soon after the outbreak of the war came to Oxford and took up study in the law school there, has published a monograph entitled "International Rivers." Mr. Kaeckenbeeck advances no theories and carefully refrains from extended dis- cussion; his purpose is simply to present his data and evidence in concise form, and this he does remarkably well. His mastery of a foreign tongue is excellent, and his presentation clear; the work as a whole possesses a unique value as constituting perhaps the only extended account in English of the gradual de- velopment of free navigation, announced at the Congress of Vienna, and ap- plied successively to the Rhine, the Scheldt, the Danube, and the Congo and Niger rivers. The international regulations for the navigation of each of these rivers he describes at length. A brief survey at the outset of the mode of deal- ing with the problem of river navigation as developed under the Roman law, the mediaeval law, the Law of Nature, and under the theory of State Sovereignty, adds to the interest of the book. Appendices dealing with other European rivers and briefly touching upon certain American rivers add to its value. Mr. Kaeckenbeeck, within the limited sphere which he has chosen, has made a real contribution to the historical study of the law of international rivers, and as a reference book upon the nineteenth century treatment of these rivers his book will be of lasting value. P^^^g ^^^^ Sayre. The League of Nations and its Problems. Three Lectures. By L. Op- penheim,M.A.,LL.D. Longmans, Green and Company. 1919. pp.xii.84. That an American critic should accuse an Englishman of being over-con- servative is perhaps only the natural result of a deep-lying temperamental
