Page:Popular Science Monthly Volume 39.djvu/278

266 We sincerely hope that the gospel of liberty, preached by Mill in his celebrated essay, and now preached anew, with a vastly enlarged array of proofs in the book to which we have called attention, will gain the ear of the world and rescue its civilization.



who know but little of the science that deals with rock-formations, and regard it as one of many perplexing 'ologies, would be surprised to see what a fascinating story the earth's geological record becomes, as told in this book. The author has not written a text-book, but a volume designed to give the general reader an understanding of the process that has molded the superficial layers of the earth's crust into the forms they bear to-day. In his preface he says: "Many a sportsman or pedestrian, we believe, pauses now and again to examine some curious stone which attracts his attention, or looks at the rock or bowlder on which he rests for a mid-day repast, and would like to understand a little of its previous history. But, not knowing where to turn for assistance, he remains ignorant of a subject of which even a slight knowledge would greatly add to the pleasure of his rambles over the country." The author states that the plan of his book is, "First, to give in simple language, .and in a style which it is hoped will not deter the reader, a brief sketch of the former history of our planet, beginning with its first appearance as a member of the solar system, and passing through all the different geological periods, with their changing scenes and various phases of life, down to the latest period, when man appeared on the scene. Secondly, to explain, however briefly, the methods by which the conclusions of geologists have been arrived at, or, in other words, to put the evidence before the reader so that he may see how those conclusions were formed, and judge for himself how far they are reasonable. To do this at all fully in a small book was of course impossible, but it was thought better to attempt brief explanations than to state conclusions which, without reasons, might seem very arbitrary. Such as are given may in some cases be inadequate or incomplete, but at least they will serve to give the reader an insight into the methods of geology, and may possibly lead some to further study, and especially to personal observation. Geology can not be learned from books alone. Observation and a little reflection will help the student far more than reading. Study should be combined with field work, and in this way only can the subject be mastered." It is now fully recognized that the culture demanded by modern life includes an acquaintance with the chief fields of science. This book introduces the reader into one of these fields in a notably happy manner.

work in the cause of road-improvement has been done in the preparation and publishing of this volume. The essays which it contains were written in competition for prizes of four hundred, two hundred, and one hundred dollars, offered by William H. Rhawn and other citizens of Philadelphia, and awarded by a board of adjudicators appointed by Dr. William Pepper, Provost of the University of Pennsylvania. The paper for which the first prize was given was written by Henry Irwin, B. A., C. E., of Montreal, assistant engineer on the Canadian Pacific Railway. As required by the conditions of competition, this essay takes up the engineering, the economic, and the legislative features of road-making. The writer gives hints as to locating roads, states what grades are allowable, what widths are required in various cases, and discusses all the other details of construction. One thing on which he lays much stress is drainage. "It is almost impossible," he says, "to make a good road on a wet, yielding soil, except by going to great expense in providing a heavy concrete foundation. ... In northern latitudes the remark is frequently made in the spring that 'the frost has heaved the road.'" Mr. Irwin says that "the proper remark to make in such a case would be, 'The road is badly drained,'" and he 