780 SCIENCE PROGRESS 



in this book and in the original papers differences are classed as essential and 

 definite which to many readers seem to be merely important differences of degree. 

 The curve showing the concentrations of adsorbed substance in adsorbent and in 

 the solution often approaches the horizontal, in which case effects similar to those 

 obtained by Fleck, von Hevesy, and others might be accounted for. 



Qualitatively at any rate, however, the experimental evidence has undoubtedly 

 shown that isotopes are extremely similar substances ; and, although one could 

 wish for a rather more detailed discussion of " con " as well as of " pro " than 

 appears in either volume of this book, the author has certainly demonstrated how 

 a space in the Periodic Table can be filled by several elements of different atomic 

 weights, and of at least very close chemical similarity. 



When other than chemical properties are discussed, the evidence as yet 

 adduced is of course scanty, and too great stress is not laid on the apparent 

 identity of the spectra of ionium and thorium, nor upon the new gas, Metaneon. 

 If these and similar cases turn out to be verified, many of the objections which 

 have been mentioned will naturally be silenced. The author's case might almost 

 have been strengthened had he dwelt less upon some of the rather doubtful 

 positive evidences, such, for example, as the relative volatilies of the emanations. 

 The last adverse remark to be made is that if Uranium X2, as a unique element, 

 merits the special name of " Brevium," surely also Radium Emanation, no less a 

 new chemical type, deserves its name of Niton ? 



Lest it be thought that this review is written in a hostile or carping spirit, one 

 may emphasise the sentiment of the opening paragraph, that to the writer's mind 

 the subject of this book represents the greatest inorganic advance since 

 Mendeleeff; and every chemist must welcome so attractive and stimulating a 

 scheme, and will admire the skill and ingenuity of its founders. 



Irvine Masson. 



A Dictionary of Applied Chemistry. By Sir Edward Thorpe, C.B., LL.D., 

 F.R.S. [Pp. viii + 830.] (London : Longmans, Green & Co., 1913. 

 Price 45.?.). 



The reviewer of chemical books in his time plays many parts. He may have to 

 place himself by turns in the frame of mind of a university professor, a schoolboy, 

 a manufacturer, a research chemist, or the man-in-the-street. At least three of 

 these mental attitudes are required if one is to review properly the present work ; 

 but, failing the requisite versatility, one may be content to look upon it as an index 

 of the correlation between scientific research and industry as viewed by the repre- 

 sentatives of each who contribute to this dictionary. From this standpoint it seems 

 as if we have far to go before the correlation is nearly close enough, at any rate if 

 the evidence here displayed is a true indication. There are noteworthy exceptions 

 among the many articles in the volume, but in the main the trail of the serpent 

 Rule-of-thumb is over them all. 



Take, for example, an article which deals with one of the greatest industries — 

 the manufacture of sodium carbonate. In the whole section on the ammonia-soda 

 process we look in vain for any curves or phase-rule diagrams, despite the fact 

 that the process really depends for its success and further progress upon phase- 

 rule researches no less than upon mechanical ingenuity. One might forgive such 

 an omission in the discussion of the older Leblanc process on the ground of its 

 evolution having taken place less systematically ; but here again some of the very 

 clear and admirable descriptions of constructional details could have been dispensed 



