490 Scientific Intelligence. 



a different way. But so long as different methods of attack split 

 up a body differently, it is evident that we have not yet got 

 down to "bed rock." Moreover, a compound molecule may 

 easily act as an element. Didymium for example has a definite 

 atomic mass, has well defined salts and has been subjected to the 

 closest scrutiny b} r some of the ablest chemists in the world ; and 

 as a seeming element it emerged from every trial. But subjected 

 to a new method of attack it decomposes at once. " We have in 

 fact a certain number of reagents, operations, processes, etc., in 

 use. If a body resist all these and behave otherwise as a simple 

 substance we are apt to take it at its own valuation and call it an 

 element. But for all that, it may as we see be compound, and as 

 soon as a new and appropriate method of attack is devised, we 

 find it can be split up with comparative ease." "Until these im- 

 portant and difficult questions can be decided," he continues, " I 

 have preferred to open what may figuratively be called a sus- 

 pense account, wherein w r e may provisionally enter all these 

 doubtful bodies as ' meta-elements.' " The meta-elernents may 

 have more than a provisional value, however. Mr. Crookes 

 points out that it is becoming more and more probable that be- 

 tween the atom and the compound, we have a gradation of 

 molecules of different ranks which may pass for elementary 

 bodies. It might be the easier plan so soon as a constituent of 

 these earths can be chemically and spectroscopically distinguish- 

 able from its next of kin, to give it a name and to claim for it 

 elemental rank. " But it seems to me the duty of a man of 

 science to treat every subject not in the manner which may earn 

 for him the greatest temporary kvSo? but in that which will be 

 of most service to science." — J. Cheni. Soc., lv, 255-285, May, 

 1889. G. F. B. 



2. Commercial Organic Analysis; a Treatise on the Proper- 

 ties, proximate analytical Examination and modes of Assaying the 

 various Organic Chemicals and Products employed in the Arts, 

 Manufactures, Medicine, etc. By Alfred H. Alleist, F.I.C., 

 F.C.S., etc., etc. 2nd Edition, revised and enlarged. Vol. Ill, 

 Part I. Acid derivatives of Phenols, Aromatic Acids, Tannins, 

 Dyes and Coloring matters. 8vo, pp. viii, 431. Philadelphia, 

 1889 (P. Blakiston, Son & Co.).— This volume of Mr. Allen's 

 excellent work fully sustains the reputation of previous ones. 

 After a hundred or more pages devoted to the general characters 

 and constitution of aromatic acids, and their consideration in de- 

 tail, the author passes to the consideration of dyes and coloring 

 matters, beginning with the nitro- and nitroso-bodies, aurine and 

 the phthaleins, passing to the azo-compounds, the rosanilines and 

 safframines, and then to the anthracene colors; ending with a chap- 

 ter on coloring matters of natural origin, chapters on the examina- 

 tion and recognition of coloring matters and the examination of 

 dyed fibers conclude the book. The entire work will be completed 

 in another part. It bears evidence of care and thorough work on 

 every page and has already become a standard upon the subjects 



