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by Commander Gorringe, for the difficulties he had to meet, whether proceeding from the tempers of men or the stolidity of natural forces, and the means by which he overcame them, are clearly described and illustrated in the interesting and often amusing narrative that forms the first third of the volume. The account of Commander Gorringe's experiences in getting the great stone afloat and across the ocean is supplemented by descriptions of the methods, also illustrated, by which other obelisks have been transported to Paris, London, and Rome. The rest of the book is mainly historical and archæological. In it are included a review of the "Archæology of the New York Obelisk," its symbolism, translations of the inscriptions on it, and its history; a "a Record of all Egyptian Obelisks," with photographs, and translations of their inscriptions; and "notes on the ancient methods of quarrying, transporting, and erecting obelisks," including all that is known on the subject. The final chapter, arranged by Professor Persifer Frazer, describes the analyses of the materials and metals found with the obelisk, and is illustrated by polariscopic sections of rocks. The work thus combines a narrative of personal adventure and professional achievement, an exhaustive historical and archaeological account of Egyptian obelisks, and the results of scientific study, in a setting in which no expense seems to have been spared to make it worthy of the subject, and to leave nothing wanting.

Experimental Researches into the Properties and Motions of Fluids, with Theoretical Deductions therefrom. By W. Ford Stanley. London: E. & F. N. Spon. 1881. Pp. 538. Price, $6.

Having been engaged in an experimental examination of the undulatory theory of fight, from which he was obliged to desist on account of failing eye-sight, Mr. Stanley took up this subject, he tells us, from the interest awakened by the previous work, and in the hope of making clear to his own mind certain points left obscure by his previous investigations. It soon, however, appeared to him that "there was yet an immense amount of work to be done in researches in the motions of fluids before theoretical principles of the sciences of hydrodynamics and acoustics could be fixed upon mechanical principles with any great precision," and he consequently entered upon the extended investigations set forth in the present volume. Of the unsatisfactory state of much of the work in this branch of physics the author instances the case of wave-motions on water. The true procedure in this case is to determine the manner in which waves are produced on the surface of water by the action of the wind, and then, as a secondary consideration, to investigate the action of gravity in bringing the surface to equilibrium. The reverse of this order, the author asserts, is usually followed, the question being made a case of the oscillations of fluids through gravitation only, and thus begged, as you have then to assume the wave in existence, while its production is the thing to be accounted for.

The first three chapters, the author states, are speculative, and he puts them forth simply as helping to a clearer conception of the nature of a fluid. In the fourth chapter he develops a theory of rolling contact of fluids moving upon static bodies; and in the fifth and sixth chapters he offers principles of conic resistance in fluids which give simple mechanical laws for the class of motions known as vortices, eddies, and cyclones. The eighth chapter is devoted to an exposition of the "principles of motive resistance to the projection of free solids in extensive fluids," and the ninth to the "diffusion of flowing forces in fluids."

These nine chapters constitute the first section of the work, the principles established in which are applied to the elucidation of the manifold phenomena of natural currents produced by the combined effects of heat, gravitation, and the earth's rotation. In the third and closing section of his work Mr. Stanley takes up the subject of the formation of waves upon the surface of water, on which he reaches conclusions not materially different from those of M. Flangergues and Mr. Scott Russell. A fourth section upon sound-motions in fluids, which should have made a part of the present treatise, the author withholds from publication until he has opportunity to go over the subject again, with the help, which he anticipates