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704 republic. Besides their own experiments, the authors, to qualify themselves for their work, visited the principal laboratories of Europe, including those of Dr. Miquel, of Montsouris; Dr. Ferran, of Barcelona; Prof. Emmerich, of Munich; Dr. Korralsky, of Vienna; Prof. Fodor, of Buda-Pest; and Dr. Fraenkel, of Berlin. The first part of the treatise relates to the examination for mineral constituents, including the determination of the weight of 6olids, of alkalinity, noxious metals, chlorine, nitric and nitrous acids, and gases; the second part, to the examination for organic impurities by the ammonia and permanganate processes; and the third part, to the bacteriological examination. To this is added a chapter on parasitical animals introduced by water into the organism, by Dr. Rafael Blanchard, of Paris. The work is illustrated by one hundred and twenty-seven engravings, sixteen photomicrographs, and five photograms of cultivations, and is published in London in Spanish by Burns & Oates.

Persifor Frazer's useful Tables for the Determination of Minerals by Physical Properties ascertainable with the Aid of a Few Field Instruments is published by the J. B. Lippincott Company in a third edition, entirely rewritten. The author's first intention was to introduce the method of determination pursued in the Royal Saxon Mining Academy at Freiberg, in a translation of Prof. Weisbach's tables; but he soon found that it would have to be modified in many particulars in order to meet the wants of American readers; and the changes and additions were so numerous as to make virtually a new book. The principle is insisted upon that every true mineral is a definite chemical compound or element, homogeneous throughout its parts, and capable of expression in a chemical molecular formula. This principle, which was at first opposed by Prof. Dana, has now been tacitly conceded by all modern writers, including Prof. Dana himself. The minerals are classified for purposes of identification into those of metallic luster, and then, subordinately, according to their colors; those of submetallic and non-metalic luster, and the color of their streak; and minerals of non-metallic luster with white or light gray streak, and according to their sectility or hardness. $2.

In A Preliminary Report on the Geology of the Central Mineral Region of Texas, which forms a part of the first Annual Report of the Geological Survey of the State, Mr. Theodore B. Comstock assumes that the region has never been adequately studied, and criticises the references to it by the geological writers who have spoken of it as betraying want of information. In his own report he gives only definite results which the facts known are fully believed to warrant. Of statements of previous authors which he summarizes a certain number have been verified by his observations, while as many more have been found incorrect; and, as a result of the field work of 1 889, a considerable amount of new and wholly unexpected structure has been worked out.

Mr. Ernest E. Thompson, in his monograph on The Birds of Manitoba (United States National Museum), has made the political boundaries of the province the boundaries also of the district included, although it does not constitute a distinct zoological province. He spent altogether about three years in the province and in his studies of birds. He offers his observations as they were made on the spot, without condensation or generalization, believing that the only right course under the circumstances. His original plan was to prepare something "after a very old-fashioned model," but widening experience caused a change of view. His own observations are supplemented by those of numerous observers in different parts of the province, and citations of other scattered published matter. From his sketch of the physical features of the province, we learn that it is plentifully, almost too plentifully, supplied with water. Besides the numerous extensive lakes indicated on the map there are thousands more of smaller extent, while the region of the Red River Valley in particular is diversified by vast stretches of marsh and lagoon. The lakes consist of sweet or live-water lakes of various sizes, fed and drained by living streams and teeming with fish; and the alkaline lakes, which are mere drainage basins, and depend on evaporation for the removal of their accumulated waters. They owe their alkaline constituents to the continual influx and evaporation of surface water slightly impregnated with alkali, through running over the prairies