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THE POPULAR SCIENCE MONTHLY. 



"We sincerely hope that the gospel of 

 liberty, preached by Mill in his cele- 

 brated essay, and now preached anew, 

 with a vastly enlarged array of proofs 

 in the book to which we have called at- 

 tention, will gain the ear of the world 

 and rescue its civilization. 



LITERARY NOTICES. 



The Autobiography of the Earth. By 

 Rev. H. N. IIdtchinson, F. G. S. New 

 York : D. Appleton & Co. Pp. 290. 

 Price, $1.50. 



Those 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 writ- 

 ten 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 be- 

 lieve, pauses now and again to examine 

 some curious stone which attracts his atten- 

 tion, 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 pre- 

 vious 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 pass- 

 ing through all the different geological pe- 

 riods, 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 rea- 

 sonable. 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 rea- 

 sons, 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 meth- 

 ods 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 rec- 

 ognized that the culture demanded by mod- 

 ern 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. 



A Move for Better Roads. Essays on Road- 

 making and Maintenance and Road Laws. 

 Philadelphia : H. C. Baird & Co. Pp. 319. 

 Price, $2. 



Important work in the cause of road- 

 improvement has been done in the prepara- 

 tion 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 ad- 

 judicators 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 north- 

 ern 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 recom- 



