534 Scientific Intelligence. 



with the aspect of this science towards the invariable substance 

 of varying matter." In it, "experimental and practical data 

 occupy their place, but the philosophical principles of our science 

 form the chief theme of the work." "In comparing the science 

 of the past, the present and the future, in placing the particulars 

 of its restricted experiments side by side with its aspirations for 

 unbounded and infinite truth, and in restraining myself from 

 yielding to a bias towards following the most attractive repre- 

 sentation, I have endeavored to incite in the reader a spirit of 

 inquiry, which, unsatisfied with speculative reasonings alone, 

 should subject exery idea to experiment, excite the habit of 

 stubborn work, necessitate a knowledge of the past, and a search 

 for fresh threads to complete the bridge over the bottomless un- 

 known." Such a standpoint as this is unique in chemical trea- 

 tises. And an examination of the book shows these claims to 

 have been fully met. Not only is the entire work based upon 

 the law of periodicity, but a vein of what the author calls 

 " scientific contemplation " runs through it, which " bears the 

 stamp of creative power and comprehends the highest branch of 

 scientific progress." In the second place, the book exhibits an 

 exceptional fidelity to details, not only along the main line of the 

 subject, but along collateral lines. Perhaps the most noticeable 

 typographical feature in it, is its wealth of foot-notes, which 

 occupy probably one-half of the entire text. These the author 

 suggests, should be read only after the large text has been mas- 

 tered. But so seductive are they and so valuable in their bearing 

 upon the subject in hand, that no reader will be likely to post- 

 pone them to a second reading. Thus for example, the first foot- 

 note considers in what the investigation of a substance or phe- 

 nomenon of nature consists. And after enumerating seven points 

 which go to make it up, the author says : " It is certain that it is 

 only possible to thus study when we have taken as a basis some 

 incontestible fact which is self-evident to our understanding ; as 

 for instance, number, time, space, movement, or mass. The deter- 

 mination of such primary or fundamental conceptions (categories) 

 although not excluded from the possibility of investigation, fre- 

 quently does not subject itself to our present mode of scientific 

 generalization. Hence it follows in the investigation of any- 

 thing there always remains something which is recognized with- 

 out investigation or admitted as a known factor." Evidently, 

 therefore, while Meudeleeff's book may not be the best one for a 

 beginner to essay, it is decidedly the most desirable one for the 

 chemical student to read at some stage of his scientific education. 

 The knowledge which it contains is indispensable in a course of 

 thorough chemical training. 



The translation, in the main, has been faithfully performed, in 

 spite of the difficulties inherent to such a task. We regret, how- 

 ever, that the original wood-cuts have not been reproduced in the 

 English edition. The thanks of English and American chemical 

 students are due the publishers for placing in their hands and their 



