454 



A' A rURE 



[February 17, 1910 



MACHINE DESIGN . 

 Elements of Machine Design. By Dr. S. Kimball 

 and J. H. Barr. Pp. viii + 446. (New York : John 

 Wilcv and Sons; London : Chapman and Hall, Ltd., 

 iqog.) Price 12s. 6d. net. 



THIS is an important work on a subject which it is 

 difficult to treat in systematic manner on account 

 of the great complexity of the conditions involved. 

 The variety of machines now made is almost over- 

 whelming, and is continually increasing, while for 

 the successful and intelligent design of machines of 

 any one class the engineer must possess a faculty 

 of invention, a sound judgment, some acquaintance 

 with commercial conditions, familiarity with work- 

 shop processes, a knowledge of the many branches 

 of applied mechanics and of physics, all the result of 

 long study and practical experience. The treatment 

 of so extensive a subject must of necessity be only 

 partial, and the primary appeal of this book is to 

 students of technical colleges. At the same time, the 

 expert draughtsman will find much of interest and 

 profit. The drawings are subordinate, and are intro- 

 duced mainly to illustrate principles. The treatment 

 is logical yet practical, very suggestive and germane 

 to the subject, and the style is attractiv-e and interest- 

 ing. The writers can speak with authority, each 

 having had experience as a professor of Sibley College, 

 Cornell University, and also as a manager of an 

 engineering works. 



The authors begin with some examples illustrating 

 the energy changes which take place in a machine 

 during a cjxle of operations, the object of the 

 investigation being to determine the maximum 

 value and range of the force actions which 

 occur. Then follows an explanation of how 

 the parts are to be designed so as to withstand 

 successfully these straining actions, and a very com- 

 plete and well-arranged collection of formulae for the 

 strength and stiffness of beams, shafts, struts, &c., is 

 given. The discussion of the considerations which 

 affect the choice of a suitable factor of safety will here 

 be found very helpful. 



The chapter on friction, lubrication, and efficiency is 

 extremely interesting and suggestive. The investiga- 

 tions on lubrication by Beauchamp Tower and later 

 experimentalists are quoted and analysed, and their 

 significance explained. Subsequent chapters are de- 

 voted to machine details, comprising springs, riveted 

 joints, screws and bolts, keys and cotters, tubes and 

 pipes, constraining surfaces for sliding and turning 

 motions, shafting and couplings, belt, rope, and chain 

 transmission, friction wheels and brakes, spur, bevel 

 and screw gears, flywheels, pulleys and rotating discs, 

 and, lastly, machine frames. 



The chapter on constraining surfaces is one of the 

 best in the book. Some of its drawings exhibit modern 

 types of cylindrical and thrust bearings, and ball and 

 roller bearings. In the general discussion the authors 

 enter fully into the permissible bearing pressures, the 

 details for securing efficient lubrication, the dissipation 

 of heat from the bearing, and all the conditions for 

 successful design. Indeed, every chapter is suggestive 

 and interesting, but enough has been said to indicate 

 NO. 2103, VOL. 82] 



the general character and scope of the work. We must, 

 however, not overlook the numerical examples which 

 are introduced at intervals, and used to illustrate and 

 suggest the proper treatment of problems in design. 

 Mention should also be made of the many references 

 to publications, to assist readers who desire further 

 information. 



Altogether, the authors are to be congratulated on 

 the production of a very instructive, well-arranged, 

 and well-written treatise on the elements and prin- 

 ciples of machine design. The book should be in the 

 library of every engineering school and college. 



THE ATRIUM OF SOUTH AFRICA, 

 jin Introduction to the Geology of Cape Colony. By 

 Dr. A. W. Rogers and A. L. Du Toit. Second 

 Edition. Pp. xiv + 4g2. (London : Longmans, 

 Green and Co., 1909.) Price 9s. net. 



THIS handbook is the second edition of that re- 

 viewed in 1905, and the progress made since then 

 in South African geology renders its appearance all 

 the more welcome. Dr. Rogers has associated his 

 colleague, Mr. Du Toit, in the authorship, and the 

 preparation of the new material has no doubt raised 

 pleasant memories of many a long campaign, in lands 

 where the horizon always seems to call one further, 

 until the rim of the world sweeps up against the 

 sunset, and another night is spent beneath the stars. 



The complete revision of the work makes it virtually 

 a new one for purposes of reference ; and the coloured 

 map is now on a larger scale, and covers additional 

 ground, notably in Griqualand West. Two sections 

 illustrate the folded margins of the colony, and the 

 broad synclinal of the Karroo system, which in places 

 measures 450 miles from side to side. The correlation 

 of the pre-Devonian rocks (p. 5) is considered in some 

 detail, and reasons are given (p. no) for the reten- 

 tion in this group of the " continental " Matsap system 

 on the fringe of the Kalahari. The Karroo system, 

 from the Lower Dwyka beds to the volcanic capping 

 of the Drakensbergen, is compared (p. 233) with South 

 .Vmerican and European strata, on the basis of recent 

 literature. The glacial Dwyka beds, composed of the 

 so-called "tillite," may be L^pper Carboniferous or 

 Lower Permian ; but the reptilian fauna places the 

 L'pper Dwyka series in the Permian. The Beaufort 

 beds, with Pareiasaurus, Oudenodon, and the fresh- 

 water molluscs Palaeomutela and Palseanodonta, are 

 paralleled by the Russian Permian. The Upper Beau- 

 fort or Burghersdorp series is, however, probably 

 Triassic ; so also are the succeeding Molteno beds, 

 regarded as equivalents of the Rhsetic. The Storm- 

 berg series, if we except the Molteno beds, is held to 

 be Jurassic. Dr. Broom has entirely re-written his 

 chapter on the Karroo reptiles, and points out that 

 Tritylodon, which he has elsewhere shown to be most 

 probably a Jurassic form, may be retained among the 

 mammals. 



The chapter on the volcanic pipes younger than the 

 volcanic Stormberg series has been expanded, but no 

 longer contains the sections of the rock-shafts at 

 Kimberley. The relationship of their igneous in- 

 filling, known as klmberlite, to melilite-hasalt (p. 364) 



