508 Notices respecting New Boohs. 



tunately occurred to Mr. Crookes that a selection of the best of 

 these — proved to be the best by actual trial in his own laboratory 

 — would be of service to chemists generally. The first edition, 

 accordingly, of ' Select Methods ' appeared in 1871 ; and, after an 

 interval of fifteen years, we are now presented with its much 

 enlarged successor. It need hardly be said that this, the second 

 edition, has been to a great extent rewritten ; and the distinguished 

 compiler of the work still continues to vouch personally for the 

 value of the processes he describes. Few chemists, probably, 

 would be disposed to undertake such a laborious task of literary 

 filtration; and Mr. Crookes undoubtedly deserves the thanks of all 

 his confreres for a sustained effort, unique in the history of this 

 science. On the other hand, the scheme is, from its very nature, 

 tinctured with some disadvantage. Some methods, not less 

 efficient than those here selected, must have been passed over 

 from sheer lack of opportunity to try them ; others, — omitted as 

 " universally known," " untrustworthy," or " doubtful," — might 

 (legitimately perhaps) have been inserted by a second author, also 

 possessed of competent ability. And so deeply is this stamp of a 

 personal judgment impressed upon the work, that it lies almost 

 without the province of logical review. When an able analyst has, 

 after experiment, stated his opinion of a given process, the attitude 

 of others must long continue to be one of simple receptivity. 



The general features of the first edition will be found to charac- 

 terize the second. There is the same perfectly just stress laid 

 on the inclusion of " rare" elements (after all, not rare) ; the same 

 range through the various departments of gravimetric and volu- 

 metric analysis (including that of gases) and what is known as 

 " technical " analysis. Volumetric processes no longer (excepting 

 for gases) occupy a separate chapter ; this is a distinct systematic 

 improvement. There is a separate section devoted to " New 

 Processes and General Methods of Manipulation " ; and the "Useful 

 Tables " are naturally more numerous than previously. 



The special aspects of Mr. Crookes's work would require more 

 space than we have at our disposal for their complete summary ; a 

 few comments will, however, suffice. The order mainly observed 

 is : — (1) lighter metals, (2) heavier metals, (3) metalloids. Take 

 Potassium. Under this heading, ten or eleven new methods or 

 modifications are adduced as meeting various conditions. Much 

 stress is laid on the platino- chloride process and the limits of its 

 accuracy, an abstract being given of the E-eport of the British 

 Association's Committee upon this subject. It would have been 

 an advantage here to have given some simple plan for obtaining a 

 platinum solution free from iridium. To the chapter on Sodium 

 little has been added ; indeed, there has been little to add. A good 

 direct gravimetric method for estimating sodium is still a deside- 

 ratum. There is a good deal of new matter under Magnesium. The 

 intricate topic of the Cerium Metals receives very ample treatment, 

 as might have been expected from the Author's special acquaintance 

 with the subject. Here the reader will find the process of fractional 



