October 29, 190S] 



NA TURE 



661 



hand. Data of every degree of untrustworthiness are 

 given in tlie text, but tlie student is debarred from veri- 

 fying the figures or referring to the original for further 

 information as to their meaning; exact references 

 should have been given in every case. Even in the 

 bibliography we would suggest that such citations as 

 " Produktion and consum. of timbre in forein coun- 

 tries, (blue book)," and " Statesman's yearbook, 

 Statist. ."Abstracts (mit statistischen Tabellen),"' are 

 hardly clear. 



Finally, while we approve the use of graphic 

 methods, we wish tliat Dr. Reyer would lay to heart 

 the golden instruction in the Board of Education's 

 '■ Syllabus of Practical Mathematics " : — " In all the 

 work on squared paper a candidate should be made 

 to understand that an e.xercise is not completed until 

 the scales and the names of the plotted quantities are 

 ulearly indicated on the paper." 



OVR BOOK SHELF. 



Etude sur la ]'aUee Lorraine ilc la Mcusc. By J. \'idal 

 de la Blache. Pp. 190; with figures and folding 

 maps. (Paris : Armand Colin, 1908.) Price 

 4 francs. 

 Captain Vidal de la Blaciie publishes in this book 

 a memoir on the development of the valley of the 

 Meuse, a subject that has engaged the attention of 

 several previous authors, including M. Cornet and 

 Prof. W. M. Davis. He points out the strilcing 

 character of this long valley, without any important 

 tributaries, yet carved out in past times by a river 

 more powerful than that which now occupies its bed. 

 He explains its independence as regards the Paris 

 basin bv the fact that its waters were led north- 

 ward into an old sea covering the Ardennes before 

 the westward slope of the Seine system had been 

 determined. The Meuse was originally joined by the 

 Moselle at Pagny-sur-Meuse, through the now 

 deserted gap between that town and Toul, and thus 

 had its primary sources in the Vosges. The author 

 relies much on the distribution of pebbles from the 

 Vosges in the older alluvium of the valley. He 

 denies that the river is decadent, though since the 

 capture of the Moselle it has lost much of its erosive 

 force; it has still an important flow, owing to the 

 supplies gathered from the rains and stored in the 

 deep and saturated gravels of its bed. 



The second part of the book relates to the influence 

 of the valley on the occupations of its inhabitants. 

 The population has become reduced (p. 143) to the 

 lowest level compatible with agricultural production, 

 and labourers are even invited from other areas. 

 Hence there is no surplus of workers who might 

 emig'rate from it to the neighbouring mining country. 

 The latter has become occupied by Belgians and 

 Italians, and the contrast of peoples and modes of 

 livinjj has become acute. The typical farmstead on 

 the Meuse is figured on p. 151, where we see dwel- 

 ling-house, barn, and stable under one great roof, as 

 in Friesland ; three separate entries, however, are 

 here provided in place of the huge doorway common 

 in the Low Countries. The history of roads along 

 this natural highway or across it is fairly given, but 

 the author stops short of the last great incident of 

 tlie valley, when the French armies were led north- 

 ward along it, as if drawn fatally to the .\rdennes, 

 while the Bavarians, representing the ancient tor- 

 rents from the Vosges, poured down after them to 

 Mou^on and .Sedan. .\s Captain de la Blache ob- 



XO. 2035, VOL. 7S] 



serves (p. 177), the mineral wealth of Lorraine has 

 led to a convergence of canals and railways inde- 

 pendent of the direction of the Meuse ; it is as if 

 this valley " avait subi aussi une capture ^conomique." 



G. A. J. C. 



CJicinical Rcat^cnts, tlicir Purity and Tests. A New 

 and Improved Text based on the Latest Edition of 

 Krauch's " Die Priifung der chemischen Reagentien 

 auf Reinheit." By E. Merck. Translated by H. 

 Schenck. Pp. vii-l-250. (London : .A. Constable and 

 Co., Ltd., 1907.) Price 6^. net. 

 Every chemist, whether engaged in analytical work 

 or not, will welcome the translation of Krauch's 

 manual into English, for the growing refinements 

 introduced into all chemical operations render a full 

 knowledge of the purity of laboratory reagents in- 

 creasingly important. 



In the present volume the properties of common 

 materials, both inorganic and organic, are given in 

 alphabetical order, the nature of the impurities indi- 

 cated, and the tests, both qualitative and quantitative, 

 described. It thus becomes a very simple matter to 

 ascertain the purity of any substance, and, as there 

 are something like 250 enumerated, it will be seen 

 that the range is fairly comprehensive. Tliere is little 

 that calls for comment or criticism. The descriptions 

 of the impurities and tests, though short, are usually 

 sufficient for the purpose, not the least valuable part 

 bein^ the references to original papers containing 

 details of the processes not found in the text. 



The original of Krauch's manual appeared in 

 German in 1888, and passed throu.s^h several editions, 

 the above translation being made from a revised 

 edition prepared by E. Merck in 1905. The names 

 of the joint authors are a sufficient guarantee of the 

 trustworthiness of the information, and the trans- 

 lation is all that could be desired. Whilst strongly 

 recommending the book we would direct attention to a 

 few omissions. There is no mention of hydrazine, 

 formaldehyde, toluene, or titanium salts, no quanti- 

 tative method s'^'cn for estimating solutions of 

 hvdrogen sulphide and ammonium sulphide, and 

 nothing is said about metallic lead, magnesium, and 

 aluminium, all of which may be regarded as not 

 uncommon reagents. J. B. C. 



Notre Floffc ahienne. By Wilfrid de Fonvielle and 



Georges Besan^-on. Pp. 234. (Paris : Gauthicr- 



Villars, 1908.) Price 6.50 francs. 

 Tins little book forms a resume of the steps taken 

 to accomplish the navigation of the air so far as we 

 have at present got. Ordinary ballooning is left out 

 of the question, and the bull< of the book is devoted to 

 the development of the dirigible, especially in France. 



Soon after the ascent of the first balloon (1783), 

 Lieutenant Meusnier wrote a memoir discussing the 

 principles on which a dirigible balloon might be con- 

 structed. This was remarkable as foreshadowing the 

 airship of to-day, especially as regards the " ballonet," 

 or method bv which the envelope can be kept rigid by 

 the internal pressure of air. But at that period no 

 engines existed bv which the necessary power for pro- 

 pulsion could be obtained. Later on, when the steam 

 engine had become developed, (jiffard built his 

 machine, the prototype of the modern vessel, and 

 made trials in Paris in 1852. Little by little further 

 improvements were made, the sie,e;^e of Paris especially 

 directing attention to the importance which might 

 attach to such an apparatus in military operations. 



Then came the electrically propelled balloons of 

 MM. Tissandier, and La France, which latter proved 

 to be the first machine to make long journevs success- 

 fullv. 



