52 



NA TURE 



[November i6, 1899 



spirit and stimulus of the science. In like manner he 

 came to the conclusion that ordinary chemical text- 

 books are unsuitable for the pupils of Volkshochschulen, 

 and the present work has been written to fill the void. 

 The case which Prof. Lassar-Cohn endeavours to meet 

 is a somewhat special one. Given an evening class of 

 young men desirous of improving their general edu- 

 cation, which is the best way of giving them some notion 

 of chemistry ? Prof. Lassar-Cohn answers this question 

 by saying that as a laboratory is a luxury which a 

 Volkshochschule cannot afford, you must content your- 

 self with experimental lectures and present the subject in 

 its broadest and most interesting aspect. 



Here again, it would seem, the prejudice of University 

 training makes itself felt, in the notion that a laboratory 

 suitable for teaching the elements of chemistry is neces- 

 sarily the large and expensively furnished apartment set 

 apart in universities for the professional study of 

 chemistry. This is indeed a common enough belief, one 

 that has led in this country to great extravagance and 

 much futile teaching. It is impossible to believe that 

 Germany would make difficulties about providing the 

 Volkshochschulen with all that is really requisite for 

 teaching, by practical work, the amount of elementary 

 physics and chemistry which should be there attempted. 

 Until this is done, until a properly coordinated course 

 of work in the laboratory and class-room can be arranged, 

 really profitable teaching \j\\\ in the opinion of the present 

 writer, be impossible. 



Whether or not we accept the author's standpoint 

 that lectures are inevitable, we must admit they may 

 be made to open out new vistas of knowledge and 

 supply a stimulus to study, and we cannot hesitate to 

 praise the book before us. Dr. Lassar-Cohn pos- 

 sesses in a high degree the faculty of exposition ; 

 he writes in a style which, for force, clearness, and 

 above all, freedom from prolixity, is uncommon 

 enough in German text-books. The matter of the 

 book, too, fully corresponds with the author's in- 

 tention. It is comprehensive without being en- 

 cyclopaedic, and is supplied with a good deal of 

 human interest. The historical element is not in- 

 troduced to any great extent, not as much, in fact, 

 as it might well be in such a book. Hardly a great 

 name in the roll of chemists is mentioned, except 

 that of Kekule. The book begins much in the orthodox 

 way, with an attempt to delimit the frontier between 

 chemistry and physics, and quickly and discreetly passes 

 on to water and hydrogen. After this come the halogens 

 and the hydracids, followed by lucid explanation of the 

 laws of chemical combination and the atomic and mole- 

 cular theories. The other chief non-metals and their 

 compounds are passed in review, and then half a dozen 

 of the metals are dealt with. Here and there chapters 

 appear dealing with special topics, such as the building 

 up of plants from inorganic substances, the preparation 

 of metals by electrolysis, the classification of the elements. 

 The treatment of these topics is excellent. The author 

 has a lightness of touch which is very agreeable, and 

 very different from the heavy hand of the compiler. This 

 is particularly evident in the treatment of organic 

 .chemistry, which is admirably reviewed in some forty 

 NO. 1568, VOL. 61] 



pages, and throughout the work there is indeed a 

 pleasant sense of freshness. To those who wish to gain 

 a general idea of the scope of modern chemistry, and who 

 cannot obtain class instruction, this book may be strongly 

 recommended. It has not the popular interest of the 

 author's " Chemistry in Daily Life" ; but it has a different 

 object, the aim being to show the philosophy rather than 

 the practical usefulness of the science. It is probable 

 that there is a considerable public to whom the book will 

 be a really valuable acquisition, and with whom it will 

 fulfil its aim of being an introduction to chemistry "in 

 leichtfasslicher Form." 



The illustrations, which are fairly numerous, call for a 

 word of criticism. They are exceedingly crude, over- 

 shaded, and often purposeless. The first figure in the 

 book, for example, is an ill-drawn dinner-bell, which is 

 to illustrate the statement that a bell when sounded 

 remains unchanged in substance, and that therefore the 

 science of sound belongs to physics ! 



In a brief postscript Dr. Lassar-Cohn enters a vigorous 

 protest against the recent decision of the German Chem- 

 ical Society to tabulate the atomic weights on the basis 

 of 0=16. He maintains that, to the beginner, it will be 

 quite unintelligible why the lightest atom should have a 

 weight of I -oi — chemical teaching, in fact, will sink back 

 to a half-alchemistic stage if the system of atomic weights, 

 which lies at .the foundation of the whole science, is to 

 be a matter for belief rather than for logical reasoning. 

 There seems to be some exaggeration here. Whatever 

 may be said in favour of oxygen being taken as i6 or 

 15-88, it is surely not a very difficult matter to explain, 

 even to beginners, the practical reasons why/<7r the time 

 being i6 has been selected. It may indeed be an ad- 

 vantage if pupils are thereby forced to realise a little 

 more fully than has been usual how atomic weights 

 actually are determined. It must be admitted, however, 

 that the question of = i6 versus H = i is well worth 

 consideration from the point of view of the chemical 

 teacher. y\, 3. 



OUR BOOK SHELF. 



Laboratory Manual. Experiments to illustrate the 



Principles of Chemistry. By H. W. Hillyer, Ph.D. 



Pp. 200. (New York : The Macmillan Company." 



London : Macmillan and Co., Ltd.) 

 This book is intended as an introduction to chemistry 

 for college students, and is written on the newer (or, as 

 we have heard it termed, the new-fangled) plan. In 

 other words, the student is asked to record what he finds 

 in his experiments, and not told what he should find. The 

 success of this newer method, as of the older one, must 

 depend on much besides the text-book ; but if it be 

 assumed that the student is anxious to learn and willing 

 to take trouble, there can be little doubt where the ad- 

 vantage lies. 



In addressing the student, the author remarks that 

 "the mere bringing of chemical substances into con- 

 ditions under which they will react has less utility as a 

 means of culture than most of the manual occupations" 

 —a just if a somewhat "superior" observation— and he 

 proceeds to give general directions which, if only ob- 

 served, will leave nothing to be desired in the student's 

 attitude of mind. Experience shows, alas ! how very 

 difficult it is to get these injunctions observed. ^. * - 



To illustrate the author's method, the following may be 



