Page:Popular Science Monthly Volume 43.djvu/869

Rh by all persons interested in the mineral resources of this country.

It is the most comprehensive work of this nature which has ever been put before the public. All puzzling measurements of quantity, etc., are reduced to the metric system, and the student can readily examine the progress of the different industries, from their earliest conception to the present time. The articles on aluminum, tin, chronology of the gold and silver industries, and the platinum group of metals are very important additions to the exhaustive statistical body of the work. The histories of the progress of metallurgy, assaying, etc., are also ably treated; and in the various papers on copper we have a perfect encyclopædia of the history, progress, values, and modes of producing this metal, which can not fail to be of great benefit to everybody interested in industrial progress.

Considering the ambitious plan of the compilation it is somewhat unfortunate that provision was not made for articles upon the uses of the precious and other metals, with a few tables showing their quantitative applications. Iron, lead, and nickel occupy a considerable portion of the work, and a wonderful amount of information can be learned about these metals and the progress of their production from the exhaustive tables that accompany the text. The onyx industry is rather summarily treated; but it appears that a difficulty existed in obtaining sufficient important data to make that article more interesting. Mr. Roth well is to be congratulated upon the very useful volume which he and his assistants, Messrs. Benedict, Ingalls, Church, Hofman, etc., have produced.

the time of the author's death, in 1888, about half of this volume had been published in parts, and about one third more was written, though incompletely. Mr. Proctor intended it to be the great work of his life, and to this end had been collecting material for more than twenty years before he began its publication. The chapters which he left in manuscript have been completed by Mr. A. Cowper Ranyard, Mr. Proctor's successor as editor of Knowledge, who has also written the part on the stars needed to fill out the plan of the work. As implied in its title, "Old and New," this treatise essays to give the notions of ancient astronomers as well as the present state of the science. The author has made a practice also of telling when, where, and by whom important discoveries and advances in our knowledge of the heavens have been made, and in this way has added much of the charm of narrative to his book. The large type, many illustrations and maps, and fine paper also contribute to make the volume an attractive one. The frontispiece consists of three views of pyramids, and in the first chapter, devoted to Ancient and Modern Methods of Observing the Heavenly Bodies, the use of the pyramids and other structures of masonry for this purpose is explained. In the same chapter are described the quadrants and astrolabes of the middle ages, and the most modern transit and equatorial instruments as well. The shape of the earth is the first subject taken up after the description of instruments. Under this head the various proofs that the earth is round are given, and the processes employed for measuring its curve are set forth. The third chapter is devoted to Apparent Motions of the Sun, Moon, and Planets, and is copiously illustrated with charts and diagrams. The author next describes the True Mechanism of the Solar System, and here has occasion to dip quite deeply into history in order to give the successive approximations to the truth arrived at by the early astronomers. He follows this account with a statement of the methods that have been devised for measuring and weighing the solar system. The sun, the moon, and each of the planets are fully described, a notably interesting chapter being made on sun-spots and solar prominences under the title The Sun's Surroundings. When his labors were broken off by his unexpected death Mr. Proctor had written nothing on the stars, the nebula?, or the Milky Way, though it was known that he intended to make these sections a special feature of the book. It was in this department of astronomy that his own work was of most original and lasting character. Mr. Ranyard has sought to follow out the author's general