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Rh on that must depend upon them. The cause of truth may be injured by overhaste; it can only be benefited by deliberation and careful examination.

essay, constituting numbers two and three of the third series of the "Johns Hopkins University Studies in Historical and Political Science," is not inferior in interest and importance to any of the numbers of either series that has preceded it. Virginia was a "mother of commonwealths," and the results of her development and her policy were impressed, in one shape or another, and to a greater or less extent, in Kentucky and the States that were formed out of the Northwest Territory. The purpose of Mr. Ingle's study is to ascertain from what these results were developed, and hew. In pursuing it, he considers the character of the country and its settlers ("Virginia and the Virginians") "The Land Tenure of the Colony," "The Organization of the Hundred," "The Fortunes of the English Parish in America," "The County System of Colonial Virginia," and "The Town." Under the last head, the curious fact is developed that towns which in other States appear variously as the original form of settlement, of spontaneous growth, or as the ready creatures of speculation, were not natural to Virginia; and that the formation of them was the object of several laborious efforts, prosecuted against a chronic indisposition of the people to settle in them or to favor them at all.

surveys upon which Mr. Becker's report is based were conducted by him as aid to Mr. Clarence King, and chiefly in the lower parts of the lode. Mr. King has already made the upper part familiar to geologists. In his work Mr. Becker had the assistance of Dr. Carl Barus, physicist, who made researches in the electrical activity of ore-bodies and in kaolinization, the results of which are incorporated here. In the report, the general account of the Comstock mines and the review of previous investigations of the lode are followed by chapters on the "Lithology of the Washoe District," with detailed descriptions of sections of the rocks prepared for microscopic examination; on the structural results of faulting, the occurrence and succession of the rocks, the heat-phenomena of the lode, and Dr. Barus's papers on "Kaolinization and on the Electrical Activity of Ore-Bodies." The relations of the minerals and the changes they have undergone are discussed very fully in the chapters on "Lithology" and "Chemistry," and the character and causes of the heat phenomena of the lode, with the various theories that have been proposed to account for them, as fully in the chapter on that subject. These heat-phenomena are one of the most famous peculiarities of the Comstock Lode, and distinguish it from all other mines and excavations under the earth's surface. The unusually high temperature was manifested in the upper levels, and has increased with the depth. The present workings are intensely hot; and, during the winter of 1880-'81, the water in one of the levels reached a temperature of 170° Fahr., at which food may be cooked, and the human epidermis is destroyed. The rapidity of the ventilation required to reduce the temperature of the air is something unknown elsewhere, yet deaths in ventilated workings from heat alone are common, and there are drifts which without ventilation the most seasoned miner can not enter for a moment. The origin of this high temperature has been attributed to the kaolinization of the feldspar in the country rock and to residual volcanic activity. No positive evidence is adduced that it is due to kaolinization, and the results of Dr. Barus's experiments on the thermal effect of the action of aqueous vapor on feldspathic rocks, so far as they have been carried out, were wholly negative. No heating effect due to this cause could be detected with an apparatus delicate enough to register a change of temperature of one thousandth of a degree C. On the other hand, there is much geological evidence pointing to a deep seated source of heat, probably of volcanic origin, or solfataric. The floods of waters which have been met in the mines can not be accounted for by any hypothesis