REVIEWS 505 



and Nomograms contains articles by E. M. Horsburgh, Schleicher and Schiill, and 

 Prof. M. d'Ocagne (pp. 278-301). The Section on mathematical models 

 (pp. 302-27) contains a short introduction by Prof. Crum Brown, and an 

 article by Col. R. L. Hippisley on closed linkages. The other Sections contain 

 lists of exhibited portraits and medals, and miscellaneous and late exhibits. 



Philip E. B. Jourdain. 



Descriptive Geometry for Students in Engineering Science and Architecture. 

 By Henry F. Armstrong, Associate Professor of Descriptive Geometry 

 and Drawing, McGill University. [Pp. iii +125, with 114 figures. First 

 edition.] (London : Chapman & Hall, 191 5. Price &s. 6d. net.) 



The arrangement, excellent figures and explanations in this book bear out the 

 author's introduction to his preface — " The writer offers the contents of this text- 

 book as the result of over twenty years' constant teaching of descriptive geo- 

 metry . . . ; ' — as it is apparent therefrom that the author is fully aware of the initial 

 difficulties and the subsequent pitfalls of the student. 



There is very grave danger that the scientific and fundamental side of the 

 engineer's training will suffer very materially from courses and text-books specially 

 designed "for engineers." 



Mathematics, physics, chemistry, descriptive geometry, and even applied 

 mechanics have all undergone the " potted " process for the engineering student, 

 much to the detriment of his mental digestive powers. 



In the present volume there is very little scope, outside the title, for criticism on 

 this point. The subject itself is a vast one, and the author has simply selected 

 those sections which are of direct value to the engineer and architect. For instance, 

 "perspective projection" is included as being a section of great importance to the 

 types of students named, but its treatment is broad and fundamental, and quite 

 suitable for anyone wishing to study perspective. The same may be said of all 

 the other sections, and even in the chapters on inter-penetrations of solids the 

 author has not descended to the level of connecting-rod ends, but has confined 

 himself to cones, cylinders, and spheres — a point of distinct merit. 



In a book which has so much to recommend it, it is to be regretted that the 

 price — 8s. td. net — is such that the ordinary teacher will hesitate before selecting 

 it as a text-book for his class, more particularly as it does not contain anything 

 (examples excepted) beyond what is usually taken by the teacher himself. 



There is one further point. The author has been teaching for twenty years. 

 While this is a distinct asset when writing a text-book, it is no reason why the 

 volume should not be up-to-date. 



The opening chapter should have contained an introduction to projection in 

 general. Projection, as such, should have been defined and illustrated, and the 

 different kinds in practical use described in outline with particular reference to 

 fundamental projection. Part I., Chapter I., is on "The Projection Planes," and 

 describes orthographical projection. In no place in this opening section, however, 

 is the student told that he is studying one phase of projection only and that phase 

 orthographical. Other forms of projection are duly treated, but no idea is given 

 that the various forms are closely related. 



This point should certainly be corrected in subsequent editions, and the student 

 given a broader outlook at the very beginning in the study of the " language of 

 engineers," as drawing is sometimes termed. 



J. Wemyss Anderson. 



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