130 



THE POPULAR SCIENCE MONTHLY. 



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 monometal- 

 lism." The argument is further carried out 

 in chapters on Paper Money and Banking ; 

 the Monetary System of Canada; Money, 

 Capital, and Literest ; and Mandatory Money 

 and Free Money; and is enforced by cita- 

 tion of The Hoarding Panic of July, 189S, 

 when business found temporary relief from 

 embarrassment in a method of its own spon- 

 taneous devising independent of legislative 

 enactments. 



The Steam Engine and otiter 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 Ency- 

 clopaedia Britannica. Starting to expand 

 that article into a university text-book, the 

 additions and changes became so consider- 

 able 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 en- 

 gine, of other aspects of the subject that ad- 

 mit of theoretical discussion, such as the kine- 

 matics 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, ac- 

 count of the forms taken by actual engines 

 and of the manner of tiieir working. No at- 

 tempt has been made to describe details par- 

 ticularly, 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 prin- 

 ciple that a student need be at no loss to learn 

 the construction of engines of the commoner 

 kinds. Under " other heat engines " are in- 

 cluded 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 Expan- 

 sion, Valves and Valve Gears, Governing, the 

 Work of the Crank Shaft, Boilers, Forms of 

 the Steam Engine, and air, gas, and oil en- 

 gines. 



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 : 

 Longmuns, Green & Co. Pp. 469. 



Had Carvill Lewis lived the ordinary 

 span of life, the problem of the glacial de- 

 posits 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 accumu- 

 lated 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 de- 

 posits 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 L-eland during a visit in 

 1885 and another in 1886. Some field notes 

 made in Switzerland, Italy, Germany, Bel- 

 gium, 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- 



