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number of this publication is devoted to a particular State. The number before us, which is marked Vol. I, No. 6, is given to Georgia. It includes a fine map of the State, a list of cities, towns, villages, and stations, an editorial article on international exhibitions, and chapters describing the State in general and relating to cotton and rice culture, lands, population, immigration, education, the representative men, the religious condition, government, finances, debt, and taxation and history of the State, with a statistical table of counties. Several of these articles are furnished by men distinguished or representative in the special fields to which the papers respectively relate.

or, The Algebra of Algebraic Numbers. By Professor Pp. 131. The object of this essay is the discussion of negative quantities of algebra, with the purpose of finding a logically developed system that shall include such quantities as special cases. The volume also includes some critical notes on the methods of reasoning employed in geometry.

Their History, Construction, and Use. By Pp. 190. Mr. Abbott has been engaged for several years in developing and applying methods of testing the strength of materials, and in this book explains such of his most successful methods as seem likely to be generally useful and interesting.

By Professor Pp. 113. This is a reprint of lectures delivered before the English Society of Arts on the subject indicated in the title, which were supplementary to a previous series of lectures on the theory of the dynamo and its functions as a mechanical motor.

By Pp. 148. This hand-book contains a complete exposition of the theory of stadia measurements, with directions for its application in the field. Tables for the reduction of observations are added which the author has used in the Geological Survey of Pennsylvania, and with them the trigonometrical four-place tables.

By Pp. 169. In this book the indicator and its object are described; its construction and action are explained; and the method of calculating the horse-power of engines is illustrated. An endeavor has also been made to explain the most important parts of the theory and action of steam, and to show the modes of working engines that have been found to be most advantageous.

By C. E. Pp. 95. In this book the historical data in connection with the figure of the earth are presented, and the important mathematical principles for the deduction of it upon the spheroidal hypothesis arc arranged in a compact form.

By Pp. 143. This is a reprint of a serial paper published in the "Sanitary Engineer" during 1884, with fifty one illustrations from drawings made for the articles by the author.

maps are intended to be full, and are very handsomely executed. The group now under notice contains two sheets of the Eastern section, two of the West-Central section, two of the Western or Pacific coast section, with a Mercator chart of telegraphic lines and electric-cable connections throughout the world; and a map on a spherical projection showing the world's submarine cables and principal telegraph lines.

of "brief records of facts of interest brought to light in the course of physiological study." The constant aim of the writers has been to present these facts with the greatest conciseness compatible with scientific accuracy.