which still clings to the old delusion that legislation may in some vague sense regulate the value of coin. Although this delusion is harmless, as now exhibited in coinage acts, it becomes extremely mischievous when the attempt is made to regulate the value of the silver and gold coin at a fixed ratio of weights under the ruling of bimetallism; and it is only in a less degree mischievous when one of the money metals is ejected from the circulation under the ruling of monometallism." The argument is further carried out in chapters on Paper Money and Banking; the Monetary System of Canada; Money, Capital, and Interest; and Mandatory Money and Free Money; and is enforced by citation of The Hoarding Panic of July, 1893, when business found temporary relief from embarrassment in a method of its own spontaneous devising independent of legislative enactments.
The Steam Engine and other Heat Engines. By J. A. Ewing. New York: Macmillan & Co. Pp. 400. Price, $3.76.
The author of this work is also author of the article on the same subject in the Encyclopaedia Britannica. Starting to expand that article into a university text-book, the additions and changes became so considerable that a virtually new work, except for parts of one or two chapters, was the result of the effort. The design has been to treat, besides the thermo-dynamics of the steam engine, of other aspects of the subject that admit of theoretical discussion, such as the kinematics of the slide valve and the kinetics of the governor and of the moving mechanism as a whole, and to give a general, if brief, account of the forms taken by actual engines and of the manner of their working. No attempt has been made to describe details particularly, but the distinguishing features of certain types have been indicated. In doing this, the greatest amount of space has been given to the less familiar forms, on the principle that a student need be at no loss to learn the construction of engines of the commoner kinds. Under "other heat engines" are included air, gas, and oil engines. The author has endeavored throughout to make evident the bearing of theory on practical issues; and the experimental study of steam engines is described at some length. In the course of the work are reviewed the Early History of the Steam Engine, the Elementary Theory of Heat Engines, the Properties of Steam and the Elementary Theory of the Steam Engine, the Behavior of Steam in the Cylinder, the Testing of Steam Engines, Compound Expansion, Valves and Valve Gears, Governing, the Work of the Crank Shaft, Boilers, Forms of the Steam Engine, and air, gas, and oil engines.
Papers and Notes on the Glacial Geology of Great Britain and Ireland. By the late Henry Carvill Lewis, M. A., F. G. S. Edited from his unpublished MSS., with an introduction by Henry W. Crosskey, LL. D., F. G. S. London and New York: Longmans, Green & Co. Pp. 469.
Had Carvill Lewis lived the ordinary span of life, the problem of the glacial deposits would have been pushed well toward solution by his efforts. One is fully convinced of this by an examination of the materials and the observations upon them accumulated by him which are now given to the public. His energy and ability are evident in his unfinished work, and, being thoroughly acquainted with geological principles and having the means to devote himself to his chosen researches, he would undoubtedly have accomplished important results. His last labors were done upon the glacial deposits of the British Isles. The whole of Scotland, nearly the whole of Ireland and Wales, and the northern part of England are included in the glaciated area of those islands. The volume before us opens with introductions by Dr. Crosskey and Mrs. Lewis, then follow five papers on various phases of the general subject. The greater part of the volume is made up of Prof. Lewis's field note books, which embody his observations made in the several glaciated counties of England and in Ireland during a visit in 1885 and another in 1886. Some field notes made in Switzerland, Italy, Germany, Belgium, and Holland are given in an appendix. From these materials we can derive Lewis's theory of glaciers as it was when his labors ceased. Not all glacialists will agree with it, for there are wide differences of opinion upon glacial theory. There is not even agreement as to matters of observation. But every one must admit that his hypothesis is clear and consistent, and requires no extrava-
