412 



NA rURE 



[March i, 1900 



book has necessarily greatly diminished. It is therefore 

 most satisfactory to note that Mr. T. Forster Brown, an 

 eminent mining engineer, and Sir Warington Smyth's 

 successor as chief inspector of the mines of the Crown 

 and of the Duchy of Cornwall, has edited a revised and 

 extended edition, in which the principal changes and im- 

 provements in coal mining are treated. The chief 

 additions made are two chapters dealmg with blasting 

 and explosives and with coal washing. In the latter, 

 coke making (a subject usually included in metallurgical 

 treatises) is also discussed. Mr. Forster Brown has very 

 wisely been careful to retain the general character of the 

 book. He has perhaps carried to too great an extent 

 his unwillingness to alter the original text. The prices 

 mentioned throughout the book, for example, refer to the 

 years 1864-6. The Saxon coal production is given in the 

 long obsolete units of Scheffel j and references are made 

 to New Granada, a country that changed its name in 

 1861, and to "the flourishing empire of Brazil," which 

 ceased to exist in 1889. Again, with regard to the 

 speculation that the Palaeozoic rocks may be continuous 

 from the Severn to the Rhine, which is described as of 

 little practical importance, no allusion is made to the 

 discovery of coal at Dover. Mr. Forster Brown, too, 

 omits to point out that the statement that there are very 

 erroneous ideas of the overwhelming importance of the 

 American coalfields as compared with those of Europe 

 is no longer accurate in view of the fact that last year the 

 United States produced more coal than any other country 

 in the world. BENNETT H. Brough. 



Untersuchiingeti iiber die C hemischen Affinitaien. Von 



C. M. Guldberg und P. Waage. Herausgegeben von 



R. Abegg. Pp. 182 and 18 tables. (Leipzig : W. 



Engelmann, 1899.) 



This latest addition to Prof. Ostwald's invaluable series 



of reprints will be welcomed by all chemists. The work 



■of Guldberg and Waage is now well known, and is 



abstracted at some length in the larger books on 



theoretical chemistry ; but we have here the complete 



■series of papers with some recent annotations by Prof. 



Guldberg, and an interesting biographical and critical 



notice by Prof. Abegg. 



The student of chemical history will do well to read 

 this volume in conjunction with No. 74 of the series, 

 which is a reprint of Berthollet's " Recherches sur la 

 loi d'affinit^." Berthollet's work was published in 1801 ; 

 Guldberg and Waage's first paper is dated 1864. Be- 

 tween these years nothing advancing the mathematical 

 theory of the subject had appeared except the unrecog- 

 nised paper of Wilhelmy on the rate of inversion of 

 •cane-sugar, and the papers of Berthelot on estorification. 

 When this is borne in mind it will be realised how great 

 and how sudden was the advance made by the two 

 Norwegians. 



The three papers contained in the reprint, and dated 

 respectively 1864, 1867 and 1879, show how, with the 

 progress of time, the ideas of the authors grew in sim- 

 plicity and generality, until in 1879 we have their theory 

 in a form differing but little from that in which it is 

 employed at the present day. The two earlier papers 

 were very little known up to 1879, and several investi- 

 gators worked unwittingly in the same field discovering 

 facts a second time. This, however, can hardly be a 

 matter for regret except in so far as it tends to bewilder 

 the student. In other respects it has only served to 

 strengthen the foundations of chemical dynamics. 



A. S. 



By Frances Theodora Parsons, 

 plates. (New York : Charles 



How to Know the Ferns. 



Pp. xiv -1- 215 ; and 



Scribner's Sons, 1899.) 

 This book is intended to serve as a popular handbook to 

 the ferns of the United States. It will probably fulfil its 

 purpose, in enabling the reader to identify the majority of 



NO. 1583. VOL. 61] 



the ferns described by means of their general habit, aided 

 by the form of the sorus. To this result the numerous 

 original illustrations, which are clear and accurate, will 

 largely contribute. An artificial key to the species is 

 provided, in which the authoress depends to a consider- 

 able extent on the degree of difference between sterile 

 and fertile fronds to characterise the main groups. It 

 is to be regretted that attention is not directed to the 

 artificial nature of these distinctions, and that the natural 

 arrangement was not adopted in the part devoted to 

 the description of the species. In this we find the species 

 of Osmunda separated in two groups, while the Ophio- 

 glossaceae are placed in the midst of the true Ferns. The 

 brief account of the reproduction of ferns on pp. 30-35 

 leaves much to be desired. The figures illustrating this 

 are poor, notably the drawing of a sporangium on p. 31, 

 while the description is bald and in places misleading. 

 No mention is made of the peculiar subterranean pro- 

 thalli of the Ophioglossateae. Had space been found by 

 the omission of irrelevant matter in the Opening chapters 

 for a clear, simply written, and well-illustrated account of 

 the life-history of ferns, with special reference to the 

 native species, the book would have been none the less 

 popular, while its educational value would have been 

 greatly increased. W. H. L. 



Laboratory Note-Book for Chemical Students. By Prof. 

 Vivian B. Lewes and J. S. S. Brame. Pp. viii -I- 170 

 (with alternate blank pages). (Westminster : A. 

 Constable and Co., 1899.) 



The authors of this book, which is essentially one for the 

 laboratory bench, are of opinion that there is room for a 

 small volume containing all the necessary description for 

 the laboratory preparation of gases, &c., together with 

 the reactions of metallic and acid radicles, in a concise 

 form, and some of the more simple quantitative experi- 

 ments suitable for students. In the treatment of a few 

 technical matters, such as the valuation of fuel, the 

 simple examination of oils, the viscosity of oils, and the 

 characteristics of explosives, the volume is in advance of 

 most similar laboratory manuals, but the plan of inter- 

 leaving the text with blank pages for the student's own 

 notes cannot be unreservedly recommended. Many 

 teachers find that such an arrangement is conducive 

 neither to neatness nor originality in the pupil's ex- 

 pression of his own observations. The method has, 

 however, its advantages ; and the objection to it does not 

 affect the text, which provides a good course of experi- 

 mental work in chemistry suitable for technical students 

 and others. 



The Elements of Co- ordinate Geometry. " The University 

 Tutorial Series." Part II. The Conic. By J. H. 

 Grace and F. Rosenberg. Pp. viii -H 315. (London : 

 W. B. Clive, 1899.) 

 So many text -books are available to day that the issue of 

 a new one is generally accompanied by an explanation of 

 its raison d'etre. The one before us is that the present 

 book seeks to develop the subject in a more gradual and 

 more explanatory manner than its predecessors, and to 

 pay more attention to curve tracing. That it succeeds in 

 this endeavour will be gathered from a perusal of its 

 pages, for no pains seemed to have been spared to lead 

 the reader up small but ever rising steps. To gather a 

 general notion of the scope of the book, we may say that, 

 after briefly describing the three varieties of conies, the 

 student is made acquainted with the general equation of 

 the second degree, and the classification of curves which 

 are represented by such an equation. This is followed 

 by more detailed information relating to various properties 

 of curves, taken at first generally and afterwards indi- 

 vidually. The exercises are graduated as much as pos- 

 sible as regards difficulty of solution, and are very 

 numerous. 



