SCIENCE. 



[Vol. XII. No. 2c 



responding to a determinate charge diminishes rapidly during the 

 first few seconds, and then varies almost as the terms of a feebly 

 convergent geometrical progression. The law of variation varies 

 with the substance, and is not always the same for disks of the same 

 substance. The values of the specific inductive capacity obtained 

 after as short a charge as possible are different for substances 

 which are apparently identical, but are always sensibly the same 

 disk. 



BOOK-REVIEWS. 

 The Law of Equivalents in its Relation to Political and Social 



Ethics. By Edward Payson. Boston and New York, 



Houghton, MifHin, & Co. 12". $2. 

 The title of this book is forbidding, and as inappropriate as it is 

 forbidding. The author's ' Law of Equivalents,' which he an- 

 nounces in such a formal manner, is nothing but the familiar truth 

 that if we wish to attain any end, no matter what, we must use the 

 means appropriate to that end ; and that if we use the wrong 

 means, we shall not attain the end, even with the greatest exer- 

 tions. The truth is one of great practical importance ; but its an- 

 nouncement in such a form, and as if it was a new discovery, is not 

 fitted to attract the reader. The author's style, too, though gen- 

 erally clear, is too dithyrambic for a philosophical work, passages 

 like the following being not infrequent : " Family — the very word 

 itself is redolent of sweetness. It is a holy, yea, a wholly divine 

 word. It fairly outtops every other word in the language. It is 

 not so much an apothegm as a treatise, not so much a treatise as a 

 te.xt, not so much a text as a sermon, not so much a sermon as a 

 poem," with much more of the same sort. The defects of style are 

 aggravated by the too frequent use of interrogative sentences where 

 declaratory ones would be more appropriate. But when these de- 

 ductions are made, there is much in the book that is good, and may 

 prove useful. Mr. Payson's special concern is moral improvement ; 

 and he insists that men are prone, and Americans especially so, to 

 use the wrong means for this purpose ; as, for instance, when they 

 try to make men good by legislation, or to make them learned by 

 simply establishing libraries and schoolhouses. In such cases, he 

 says, we do not offer nature the right equivalent, we do not use the 

 right means to reach the desired end. He rightly insists, also, on the 

 importance of time as a condition of moral and intellectual improve- 

 ment, reminding us that such improvement must necessarily be 

 slow, and that changes in the beliefs and practices of a nation can 

 only take place when the progress of events has prepared the way. 

 He finds in the American people a tendency to look for some great 

 spiritual movement as wonderful in its way as the great material 

 advance of the past hundred years, and resulting in the regenera- 

 tion of society ; and he maintains that such expectations are un- 

 warranted. Mr. Payson's views are in the main in accord with 

 those of most judicious thinkers; but his work would have been 

 more interesting and more useful if it had been written in a soberer 

 and more philosophical style. 



Lectures on Geography. By Lieut. -Gen. R. Strachey. London 

 and New York, Macmillan. 12°. $1.25. 

 The University of Cambridge, about a year ago, accepted the 

 proposal of the Royal Geographical Society to provide a lecturer on 

 geography with the aid of funds to be supplied by that society. As 

 an introduction to the lectures on this science, new to the Cam- 

 bridge University, the council of the society was requested to ar- 

 range a course of lectures illustrative of the general character and 

 scope of the instruction in geography suitable for a university 

 course. In compliance with this request, a course of four lectures 

 was delivered by Gen. R. Strachey, president of the Royal Geo- 

 graphical Society, which have now been published in the form of a 

 book. Strachey designates as the aim of geographical science, to 

 investigate and delineate the various features of the earth ; to study 

 the distribution of land and sea, the configuration and relief of the 

 surface, position on the globe, and so forth, — facts which deter- 

 mine the existing conditions of various parts of the earth, or which 

 indicate former conditions ; and to ascertain the relations that exist 

 between those features and all that is observed on the earth. On 

 account of this point of view, the book is especially valuable. Since 

 the importance of physical geography has become recognized, the 



tendency has been to underestimate the value of topography, in the- 

 same way in which systematic botany and zoology became neglected 

 when biology became the favorite study. Strachey first discusses 

 the astronomical relations of the earth, its form and magnitude, and 

 the history of its measurement. Appended to this is a chapter on 

 map-making, in which he dwells upon Tissot's projections, the 

 principles of which are unfortunately not yet sufficiently known 

 either^ in England or in America. After a brief historical sketch of 

 the development of our geographical knowledge, he passes to a 

 brief review of physical geography and to considering the relations- 

 of vegetable and animal life to terrestrial features. He concludes 

 with some remarks on the influence of geographical conditions on 

 man. The book is clearly written, and we hope it will be widely 

 read, as the author, by his terse and interesting treatment of the 

 subject, impresses the reader with the importance of disseminating 

 and promoting the science of geography. 



Les Formes du Terrain. By G. DE LA NoE. Paris, Imprimerie 

 Nationale. 4°. 



Lieut. -Col. D. de la Noe, of the geographical service of the 

 French army, has prepared, with the collaboration of M. Emm. de 

 Margerie, an elaborate treatise on the forms of the ground. It is 

 of both geological and geographical interest. Under the first head- 

 ing we should place the argument for the derivation of land-relief 

 by sub-aerial denudation, the evidence for the origin of valleys by 

 stream-erosion essentially independent of fractures, and other dis- 

 cussion of processes ; under the latter heading we should include 

 the description of plateaus, valleys, and other topographic elements, . 

 in connection with the conditions of their origin and development. 

 The deductive considerations are fully supplemented with illustra- 

 tions in a large volume of plates, m^ny of which are reproductions 

 of excellent topographic maps, chiefly of French localities. The 

 relation of the activity of streams to their controlling base-level re- 

 ceives much more explicit attention than is common with European 

 authcs, and the sections in which this large problem is discussed- 

 are very profitable reading. The same may be said of the expla-- 

 nation of cross-valleys such as occur in the Jura Mountains. They 

 are shown to traverse the anticlinal ridges where the structural arch, . 

 if complete, would be lowest. The list of authors quoted is re- 

 markably full, and American writers receive a large share of notice. 



Leibniz's New Essays concerning the Hitman Understanding.. 

 By John Dewey. Chicago, S. C. Griggs & Co. 16-^. $1.25., 



This work is the latest issue in the series of ' German Philosoph- 

 ical Classics for English Readers,' now publishing under the edi- 

 torship of Prof. G. S. Morris. The plan of the series does not con-- 

 template the complete exposition of any philosopher's views, but- 

 only of some one of his masterpieces. This plan has some advan- 

 tages, but also some disadvantages ; and these latter are specially 

 prominent in the case of Leibniz, whose mental activity was so- 

 multifarious. He was by no means a mere philosopher, and even- 

 in philosophy the ' New Essays ' present but a small portion of his 

 views. Professor Dewey has seen this, and endeavors, so far as 

 his space permits, to remedy it. He remarks that " Leibniz, like - 

 every great man, absorbed into himself the various thoughts of his- 

 time, and in absorbing transformed them. He brought into a fo- 

 cus of brilliancy the diffused lights of truth shining here and there. 

 He summed up in a pregnant and comprehensive category the 

 scattered principles of his age." Some of us will regard this enco-- 

 mium as a little extravagant, yet, at all events, it shows what Leib- 

 niz attempted to do, and hence Professor Dewey has found it 

 necessary to enlarge his plan a little, and give some account of 

 those doctrines of his author not presented in the ' New Essays.'' 

 He has, we think, given too much attention to the theories of 

 monads, and pre-established harmony, which are products of im- 

 agination rather than of reason ; while, on the other hand, he has 

 taken no notice of Leibniz's attempt to reconcile Infinite Goodness 

 with the existence of evil. In dealing with the ' New Essays ' 

 themselves, which were written in reply to Locke, Professor Dewey 

 has to present the views of both philosophers to a considerable ex-- 

 tent ; and in doing so he clearly reveals his own philosophical 

 standpoint. He is a disciple of Kant and Hegel, and looks upon^ 

 Leibniz as their forerunner, while Locke's work is in his eyes little- 



