754 



NATURE 



[February io, 192 i 



that the glaciers of Savoy more than rivalled 

 those of Grindelwald, already known through 

 Scheuchzer's "Itinera Alpina." 



De Saussure married early, and as his wife added 

 to his means he was able to gratify his love for 

 travel. Though at times suffering from dyspepsia, 

 he had a strong constitution, and was for more 

 than ten years after 1774 able to lead, with but 

 one interruption, "a life of various activity as a 

 hard-working professor, a man of science, a citi- 

 zen, and a mountain traveller." In this time he 

 made his principal .-Mpine explorations, which cul- 

 minated in 1787-88 and 1789 in the ascent of 

 Mont Blanc, the stay for thirteen days on the Col 

 du Geant, and the tour of Monte Rosa. But evil 

 times were approaching, for the Revolution in 

 France soon found its imitators at Geneva. 

 De Saussure 's sense of duty drew him into politics 

 in the vain hope of averting their evils, with the 

 result that he was impoverished and his life more 

 than once in peril. Dr. Freshfield gives us the 

 pitiful story in all its details until in 1794 

 de Saussure had a stroke of paralysis which, 

 though his brain remained clear and he was able 

 to write two volumes of his " Voyages " and to 

 seek alleviation by visiting baths, ultimately 

 proved fatal on January 22, 1799. 



Dr. Freshfield has spared no pains in accom- 

 plishing his task, which has evidently been to him 

 a labour of love. De Saussure was the great fore- 

 runner of scientific Alpine exploration — a man 

 better qualified than any successor until the days of 

 Principal J. D. Forbes. The latter corrected some 

 of the mistakes into which his illustrious pre- 

 decessor had fallen, and put the question of glacier 

 motion on a surer footing, about the year 1843, in 

 his "Travels through the Alps of Savoy and other 

 Parts of the Pennine Chain." This gave an 

 increasing stimulus to Alpine travel, which culmin- 

 ated in the foundation of the Alpine Club in 1857, 

 since which date scientific investigation of the 

 Alps and the conquest of mountain difficulties have 

 made wonderful progress. It is scarcely more 

 than 120 years since de Saussure died, yet the 

 pictures representing him on his greatest glacier 

 excursion, and some of his geological speculations, 

 seem to us strangely antiquated. Nevertheless 

 they show him to have been a man of true courage 

 and of a really scientific mind ; and this reference 

 to pictures reminds us that Dr. Freshfield has 

 added to the value of his work by a number of 

 well-selected illustrations, among which are not 

 only excellent portraits of de Saussure and of 

 some of his relations and friends, but also repre- 

 .sentations of places of interest in his history. 



T. G. BONNEY. 



NO. 2676, VOL. 106] 



X-Ray Analysis and Mineralogy. 



Lehrbuch der Mineralogie. By Prof. P. Niggli. 

 Pp. xii + 694. (Berlin: Gebriider Borntraeger, 

 1920.) Price 80 marks. 



THIS book, written by the professor of 

 mineralogy and petrography at the Univer- 

 sity and "Technischen Hochschule" of Zurich, 

 but published in Berlin, is a comprehensive work 

 of some originality. It is illustrated by a large 

 number of figures, which are practically all repro- 

 ductions of drawings made by the university artist 

 from material supplied by the author. The result 

 is doubtless effective from the author's point of 

 view and for rapid production, but the illustra- 

 tions are much coarser than w-ould satisfy an 

 average author or publisher in this country, espe- 

 cially in the case of so large and expensive a book. 



The work possesses a particular value, how- 

 ever, as being that of a colleague of Prof. Laue, 

 who was called from Munich, after his discovery 

 of the diffraction of X-rays by the planes of atoms 

 in crystals, to become professor of physics at 

 Zurich University, and this fact is revealed by 

 the constant references to the analysis of crystals 

 by X-rays. Indeed, it must prove somewhat em- 

 barrassing and bewildering to a student who is 

 not of some years' standing in scientific study 

 to find in the first few pages statements which 

 really embody the complex results of the most 

 recent research — on the structure of the atom, or 

 on the screw-structure of certain point-systems, for 

 instance — ^alongside the most elementary treat- 

 ment of the properties of crystals. It amounts 

 more or less to the revelation of their innermost 

 point-system and space-lattice structure before 

 even the obvious characters and attributes of 

 crystals have been touched upon. 



The book is, indeed, in its general character, 

 very like a collection of notes for lectures, illus- 

 trated by wall diagrams, only very rarely going 

 into any detail with the subject in hand at the 

 moment. Even the names of original authorities, 

 when mentioned at all, are only given as an after- 

 thought in brackets, or in an occasional note in 

 small print, while references to published memoirs 

 are entirely absent. However, a list of text- 

 books and works of reference is given at the 

 end of the book. The lecture-room impression is 

 still further emphasised by the large amount of 

 tabular matter in the book. Thus the historic 

 sequence of the acquirement of our knowledge of 

 crystals is practically ignored, and information of 

 all kinds — old and new, some easy of compre- 

 hension and some quite beyond the understanding 

 I of all but those well versed in the elements of tht 



