April 19, 1906] 



NA TURE 



579 



many cases is rather crude, and with the directions 

 for the experiments which constitute the main part 

 we are not well satisfied. Surely in a calorimeter 

 experiment it is not well to have the water so high 

 as 40 C, especially when a thermometer reading to 

 fifths is used; and surely, also, it is bad science to 

 teach a boy that he can ascertain the temperature of 

 a Bunsen flame by heating a 32-gram mass of copper 

 in it and transferring it to a calorimeter. If this is 

 done, is he too young to be shown at the same time 

 that a small bead of copper will get visibly hotter 

 (judging from tint), and that even a very thin platinum 

 wire will melt in a Bunsen burner? The temperature 

 found in the experiment with the copper ball is less 

 than iooo C. The questions at the end of each 

 chapter are the best things in the book. Many are 

 based on phenomena with which the boy will have 

 acquired familiarity in his sports and other amuse- 

 ments, and these will certainly encourage him to take 

 an interest also in more serious pursuits ; but the 

 problem on the hanging of a man strikes one as 

 rather too brutal for a school-book. 



(3) The volumes by Mr. Jackson and Mr. Allen 

 consist of collections of examples. Those brought 

 together by Mr. Jackson are of an elementary char- 

 acter. There are about 600 classified according to 

 the branches of physics to which they relate, and 

 these are followed by fifty test papers of mixed 

 problems, each paper containing about ten questions. 

 Thus we have here about 1000 questions the order 

 of difficulty of which reaches practically that of the 

 intermediate examination in the University of London. 

 This collection will certainly be welcomed by a large 

 number of teachers under the Board of Education and 

 in technical schools. The advanced questions have 

 been so constructed as to lead to reasonable results. 

 Answers are provided only to the classified questions. 



(4) The collection made by Mr. Allen is of a much 

 more advanced character, viz., that of a final pass 

 or honours degree in physics. The problems are 

 selected in the main from examination papers set by 

 the London and Victoria Lmiversities. Answers are 

 given, and these the present reviewer proceeded to 

 test, but he had omitted to observe an introductory 

 note by Prof. W. Stroud : — 



" Answers are appended to the problems. This is 

 the only feature of the book I rather regret, but they 

 are inserted in the interests of private pupils. I should 

 be delighted if only some of the answers were wrong, 

 so that students (whose notion of working examples 

 is to juggle with the numerics in a question so as to 

 get the numeric in the answer) might be righteously 

 confounded, but I have no hope; for Mr. Allen's 

 carefulness and exactitude are such that in his preface 

 he does not even tell the users of his book that ' any 

 corrections to the answers will be gratefully re- 

 ceived. ' " 



We commend the book as an aid to the simplification 

 of the work of a teacher, but at the same time we 

 hope that it will not encourage him to put altogether 

 aside the labour of compiling his own problems based 

 on his own experiments and study. Such examples 

 are of far greater value both to teacher and pupil. 



(5) With the aim which the writers of this volume 

 NO. 1903, VOL 73] 



have set before themselves we have very full sym-- 

 pathy. It is certain that the academic method of 

 teaching physics tend-, to discourage a certain class 

 of boy from paying any attention to his subject. To 

 remove this fault a less formal method is desirable, 

 especially in schools. Ultimately the youth who 

 desires a sound knowledge must be willing to learn- 

 by logical methods, for it is by these only that ac- 

 curate ideas can be acquired. But unless he is a born 

 student his interest must first be aroused. He must 

 be led to see that an intelligible account can be given 

 of the mode of action of many of the puzzling pheno- 

 mena which surround him ; he must learn that things 

 with which he has been familiar are not events iso- 

 lated completely one from another so that each has 

 no bearing on the other, but that a knowledge of one 

 contributes to his knowledge of another. In this way 

 a desire for further knowledge is awakened. 



We have also considerable sympathy with the way 

 in which this aim is carried out. Their book is full 

 of illustrations, largely from half-tone blocks — motor- 

 cars and express trains in full motion, eight-oared 

 shells, small engine attached to short train, looping 

 the loop, charming children swinging on a gate (so- 

 different from the ordinary wood-cut children), photo- 

 graphs of real ripples on a pond, engines, turbines, 

 and other machinery, the lifting-magnet with its five- 

 ton load of iron, mining coal with compressed-air 

 drill — these are some that meet the eye as the pages 

 are rapidly turned over. Sometimes, indeed, the ap- 

 plication seems rather indirect. Thus a half-tone 

 figure of a man hard at work on the top of a hay- 

 cart is labelled, " Haying : A man cannot work 

 unless he consumes food." But, even in such a case, 

 the picture is clearly intended merely to call up a 

 series of real events, and not to portray any one 

 with brutal accuracy. History is also called upon to 

 contribute ; knowledge has only gradually been ac- 

 quired. The boy gets an idea of its growth ; the 

 "heroes" of science are introduced to him (but 

 without portraits !). 



All this is excellent, and will work well. Our only 

 regret is that so much accuracy had to be sacrificed 

 in the text in order to carry out the scheme completely. 

 Is not it better, perhaps, to postpone the explanation 

 of some things until a safe foundation for true know- 

 ledge has been obtained? The pupil will require to 

 unlearn many of the statements made here, and this 

 will certainly induce a period of distrust. Some will 

 never unlearn them. However, the suggestion that 

 a book of this kind might be better curtailed is the 

 only critical one we have to offer. 



MAXIFACTURE OF ALUMINIUM. 

 The Production of Aluminium ami its Industrial Use. 

 By Adolphe Minet. Translated, with additions, by 

 Leonard Waldo. Pp. vi + 266. (New York: John 

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

 1005.) Price 10s. 6d. net. 



THIS book brings together the theory and practice 

 of the aluminium industry in a complete and 

 readable form. It commences with a more or less 



