Page:Popular Science Monthly Volume 36.djvu/577

Rh senses, the imagination, thinking, the sensibilities, language, the will, learning music, the use of books, and "training for freedom." There must be method in the performance of the teacher's work; hence we have a series of chapters on "Methodology." In "Man and his Method" the principle is enforced that, important as the method may be, the man behind it, who should inspire it, is more so. Method in questioning and in teaching arithmetic is treated with some fullness. The value and purpose of examinations are estimated. "The Ideal Schoolmaster" holds up the objective toward which every teacher should strive. "The True Function of a Normal School" is a paper which was awarded the prize of the American Institute of Instruction in 1885. "Advice to Young Teachers" embodies the substance of several addresses to graduating classes of the normal school. In them "Independent Thinking" and "Training for Citizenship" are prominent topics.

field work of the investigations recorded in this volume occupied the most of three seasons, beginning in 1883. There remained to complete the examinations satisfactorily the investigation of some important general problems affecting the whole region. Among these were indications afforded by the paleontology and structure of a previously undetermined non-conformity existing in the Coast Ranges. These were confirmed. Another investigation related to a possible connection between the formation of ore deposits and the metamorphism of the Mesozoic rocks. A third special inquiry was directed to determining whether the deposition of cinnabar is still taking place at Sulphur Bank and Steamboat Springs, and, if so, under what conditions the solution and precipitation of cinnabar and the accompanying mineral occur. The author finds that the quicksilver deposits lie along the great axes of disturbance of the world. One of these is on the line of the principal mountain systems of Europe and Asia, and the other coincides with the western ranges of the Cordilleran system of America. The principal mines are at Almaden in Spain, Idria in Austria, Huancavelica in Peru, and those in California. From 1850 to 1886 California supplied nearly half the product of the world, but is not probably destined to maintain the same rank in the future. Quicksilver was first recognized as occurring at the croppings of the new Almaden mine in 1845. But few other minerals occur in considerable quantities with the ore. Among them are pyrite or marcasite, arsenic and antimony, and sometimes copper ores, while other metalliferous minerals are comparatively rare. The principal gangue seems to be silica or carbonates. The cinnabar appears to have been deposited solely in pre-existing openings, and never by substitution for rock. The fissure systems, which are always present, are very irregular, and deposits can not conveniently be classified according to existing systems. All of them seem to have probably been deposited in the same way from hot sulphur springs. At Sulphur Bank cinnabar is now being precipitated from heated waters largely by the action of ammonia; at Steamboat Springs it is being deposited without complications from the presence of ammonia. In dealing with the processes by which the ore has been dissolved and precipitated in nature, it has been shown by experiment and analysis that cinnabar unites with sodium sulphide in various proportions, forming soluble double sulphides, and that these compounds can exist in such waters as flow from Sulphur Bank and Steamboat Springs, either at ordinary temperatures or above the boiling-point. The quicksilver is probably derived from granitic rocks by the action of heated sulphur waters, which rise through the granite from the foci of volcanic activity below that rock.

is a volume of the attractive "Riverside Library for Young People," and is intended to tell readers, in a style free from minute details and technicalities, all that relates to coal and to procuring it from the earth. The information has been gained for the most part, the author says, from