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fourth. In the four succeeding chapters, the forms of energy constituting heat, light, sound, and electricity are considered, with such illustrative examples as exhibit the essential features of each group. A brief summary of the principles of machines forms the closing chapter. A new feature of the book is a review at the end of each chapter, consisting of principles and topics, and a number of problems. Simple restatement of principles in the order of the previous discussion has been avoided, with the object of showing the truths enunciated in new relations and with added force. The text throughout is fully illustrated.

Eminent Israelites of the Nineteenth Century. By Henry Samuel Morais. Philadelphia: Edward Stern & Co. 1880. Pp. 371. Price, $2.

The careers of the hundred Jews, whose portraits Mr. Morais has presented in this volume, speak much for the inherent vitality and power of a race so long proscribed. The sketches are brief, much too brief to do justice to many of their subjects, but they are in the main judicious and are full of interest. The labors of these eminent Hebrews take a wide range. Literature, theology, music, philanthropy, statesmanship, and commercial pursuits all have their representatives, many of whom have achieved not only distinction, but positions of the very first rank. They are as diverse in their nationalities as in the character of their labors, coming as they do from all European states, as well as from America. The record as a whole is one with which Jews have reason to be gratified, while it is interesting and instructive to a wider circle.

Manual of Hydraulic Mining, for the Use of the Practical Miner. By T. F. Van Wagenen, E. M. New York: D. Van Nostrand. 1880. Pp. 93.

Placer-mining, the author states, is, when economically conducted, as certain of good returns as any ordinary avocation. Auriferous gravel deposits are very extensive on the Pacific coast, and, as the plant necessary is comparatively inexpensive, the miner has a wide field for remunerative work. He must, however, conduct his operations with a knowledge of the nature of his materials and the most efficient way of working them to secure success. Most miners at present engaged in hydraulic mining, Mr. Van Wagenen says, have but slight knowledge of physics, and are more or less rusty in their arithmetic, so that many errors are made in construction and operation, which prove costly experiments. He has therefore attempted, in this little manual, to give, in a clear and concise form, the information needed to avoid such errors. Among the subjects briefly treated are the use of decimals; the methods of finding areas and volumes; the pressure of water when at rest, and its flow through orifices and flumes; the proper method of constructing flumes, their grades, size of nozzles, etc. Tables of square and fifth roots of the numbers commonly entering into the miner's calculations are given at the end of the book.

Deep-Sea Sounding and Dredging. A Description and Discussion of the Methods and Appliances used on board the Coast and Geodetic Survey Steamer Blake. By Charles D. Sigsbee, Lieutenant-Commander U. S. Navy. Washington: Government Printing-Office. 1880. Pp. 208.

Lieutenant-Commander Sigsbee was in charge of the Blake for the four years from December, 1874, and during this time prosecuted extensive researches relative to the condition of the deep-sea bottom. During the winter of 1874-75 soundings were made off the mouth of the Mississippi River, the total number of miles being 2,505. Nearly as many miles of soundings were taken in the Gulf of Mexico in the summer of 1875, and in the winter of that and the next year a system of east and west lines was run across the great bank west of the Florida Peninsula. Others were run on the northern portion of the bank, and a number from the delta of the Mississippi out to sea, closing with a line from the South Pass to the Yucatan Bank, and one from Alacran Reef to Tortugas. The remaining years were devoted to further soundings in this portion of the waters of the American coast. The Blake was very thoroughly fitted out for her work. Her party was one of the first to use piano-forte wire for deep-sea dredging and trawling, and the experience with it showed it to be much better than