l82 



NA TURE 



[April i 5, 1909 



These, with the concise and illuminating descriptions 

 in the text, should give any reader of ordinary 

 intelligence a very fair idea of the marvellous dis- 

 coveries of modern science regarding the things and 

 movements around him. 



William E. Rolston. 



RARE ELEMENTS. 

 Introduction to the Rarer Elements. By Dr. Phillip E. 

 Browning. Second edition, thoroughly re- 

 vised. Pp. x + 207. (New York: John Wiley and 

 Sons; London: Chapman and Hall, Ltd., 1908.) 

 Price 6s. 6d. net. 

 TAURING the last few years our knowledge of the 

 AV chemistry and oroperties of the rarer elements 

 has been largely developed, and the scientific and com- 

 mercial interests connected with them having assumed 

 considerable importance, the publication of a second 

 edition of the above useful handbook is to be wel- 

 comed. 



The scheme of the work remains the saaie ns in 

 the edition of 1903 ; with each element an account is 

 given of its discovery, occurrence, extraction, proper- 

 ties, &c., concluding with more or less voluminous 

 details of experimental research work. The revision 

 has been very thorough ; some matter dealing with 

 supposed elementary substances, the existence of which 

 has since proved more than doubtful, has been removed 

 —for example, the so-called elements etherion, lucium, 

 glaukodymium, &c. A chapter on radio-elements by 

 Dr. B. B. Boltwood is included, and the section on 

 rare earths has been largely increased, and much 

 valuable matter added to it. 



The description of niobium and tantalum has been 

 brought up to date, and all that is known of the latter 

 interesting and very valuable metal, with its chem- 

 istry and unique properties, is given. The gases of 

 the atmosphere, argon, helium, krypton, neon, and 

 xenon, with their history and properties, are described 

 in detail, and several pages are devoted to an account 

 of some of the technical applications of the rarer 

 elements which greatly emphasises the importance of 

 research among these practically unknown substances ; 

 the book concludes with a series of tables for the 

 qualitative separation of the rarer elements. 



Speaking generally, as might be expected from the 

 repute and position of the author, the work is thor- 

 oughly practical and trustworthy, and is confined to a 

 brief description of known facts, the author having 

 wisely refrained almost completely from touching 

 upon the huge mass of speculative matter that has 

 unhappily been woven into this branch of chemistry; 

 no mention is made of the alleged transmutation of 

 copper into lithium by radium emanation, and no 

 surmises are given of the results that may be ex- 

 pected to follow the production of so many pounds of 

 radium, &c. ; in fact, the brevity is carried to an 

 extent that is almost to be regretted, but what is 

 given is to the point. The chapter on the radio-active 

 elements commences with a brief account of the dis- 

 covery of radio-activity by M. Henri Becquerel, and of 

 radium by P. and S. Curie and G. Bemont, with the 

 properties of uranium, ionium, actinium, thorium, &c., 

 NO. 2059, VOL. 80] 



and the section concludes with a table of radio-activi- 

 ties giving the " radiation emitted," " disintegration 

 constant," and "half-value time period" for all the 

 known radio-elements. 



Much valuable matter has been added to the section on 

 rare earths ; a list is given of more than 170 rare-earth 

 minerals, with the composition, percentage of yttria, 

 ceria, thoria, and zirconia, so far as is known in 

 each case; and in the portion dealing with the 

 chemistry, a diagrammatic scheme for their separation 

 is shown ; this diagram is a novelty, and will be found 

 a distinct help in elementary work on rare earths, 

 but considering the obscurity that undoubtedly still 

 surrounds the reactions of many of these bodies it can 

 only be taken as suggestive. 



It is much to be regretted that little or nothing is 

 said about the spectra of these obscure bodies, parti- 

 cularly as it is by the study of their spectra that most 

 of them have been recognised and isolated ; the ex- 

 tremely characteristic spark spectra of yttrium, sama- 

 rium, europium, ytterbium, scandium, and other 

 elements are passed over without notice ; when we 

 take as only one instance the fact that the very rare 

 element scandium can be directly detected in minerals 

 containing it by a single observation, this is the more 

 remarkable. 



We may give as an instance of the present activity 

 of research among the rare earths the fact that since 

 this edition went to press the announcement has been 

 made by G. Urbain and by Auer von Welsbach of the 

 decomposition of ytterbium into two distinct sub- 

 stances. 



It is a very great pity that the work has not been 

 properly inde.\ed ; brevity in this direction is a decided 

 disadvantage, and takes much from the usefulness of 

 the work. J. H. G. 



.4 GENERAL HISTORY OF SCIENCE. 

 Alts der Werkstatt grosser Forscher. Allgemein- 

 verstiiiidliche erlduterte Abschnitte aus den Werken 

 hervorragendcr Naturforscher aller Volker und 

 Zeiten. By Dr. Friedrich Dannemann. Dritte 

 Auflage. Pp. xii + 430. (Leipzig: W. Engelmann, 

 1 90S.) Price 6 marks. 



DR. D.'\NNEM.\NN'S book represents an attempt to 

 trace the gradual growth of scientific knowledge 

 by a superficial examination of critical epochs in 

 which some new discovery has been made available or 

 some truth apparent. It seems a very desirable, as it 

 is a very pleasant, task to survey the whole history 

 of natural science, to recall the men whose genius 

 and achievements have widened the outlook, and given 

 force and direction to new researches. Such a study 

 may be pleasantly impressive and momentarily 

 stimulating, but while it lacks in thoroughness and 

 precision its educational value must be small. A 

 student of a particular department of science should 

 know, it is true, the successive stages by which that 

 subject has advanced, and the author is quite justified 

 in intimating that the stud}' of the original memoirs 

 in which the great masters have developed their 

 results, in the language in which they have expressed 

 themselves, is eminently calculated to present the 



