1018 



SCIENCE. 



[N. S. V(iL. XVI. No. 417. 



fires are unknown to him ; his little crop 

 hangs under and over the firmament of 

 stars, and sails through whole untracked 

 celestial spaces, between Aries and Libra; 

 nevertheless it ripens for him in due sea- 

 son, and he gathers it safe into his barn. 

 As a husbandman he is blameless in dis- 

 regarding those higher wonders; but as a 

 thinker, and faithful inquirer into Nature, 

 he is wrong. So likewise is it with the 

 historian, who examines some special as- 

 pect of history ; and from this or that com- 

 bination of circumstances, political, moral, 

 economical, and the issues it has led to, 

 infers that such and such properties belong 

 to human society, and that the like circum- 

 stances will produce the like issue; which 

 inference, if other trials confirm it, must 

 be held true and practically valuable. He 

 is wrong only, and an artisan, when he 

 fancies that these properties, discovered or 

 discoverable, exhaust the matter; and sees 

 not, at every step, that it is inexhaustable. " 



Having thus established the ideal by 

 which we shall judge the histories of 

 physics, let us see how closely the published 

 works on the siibject satisfy that ideal. 

 We are compelled to admit at the start 

 that there is one characteristic in the ideal 

 history which no one has as yet attempted 

 to embody in his work. This is the recog- 

 nition of the relations between the con- 

 cepts of physics and those of other subjects, 

 *. e., the writers of physical history have 

 shown themselves to be artisans rather 

 than artists; they have failed to perceive 

 that there is a whole and that only in the 

 whole is the partial to be truly discerned. 

 It is thus evident that this discernment of 

 the whole is beyond the present attainments 

 of the scientific historian. Its realization 

 is reserved for some future historian and 

 , offers to him a most enticing and remuner- 

 ative field. 



If then we pass over this requisite of an 



ideal history as being at the present time 

 a Utopian ideal, what do we find? We 

 shall find that there already exist several 

 very satisfactory books upon the history 

 of our subject. Thus some of the chapters 

 in Whewell's ' History of the Inductive 

 Sciences,' and especially some in his 'His- 

 tory of Scientific Ideas,' as the later edi- 

 tions of his 'Philosophy of the Inductive 

 Sciences' are called, will be found to be 

 very satisfactory. The best part of the 

 work is, in my opinion, that which deals 

 with the ancients and the middle ages. In 

 fact, in this portion of the book he seems 

 sometimes to move towai-d the realization 

 of the first point in our ideal history— the 

 point which we have dismissed as at pres- 

 ent Utopian. In the later parts of the 

 work he falls back into the much easier 

 task of describing discoveries in their 

 chronological order and explaining theni 

 in popular ways. 



Another excellent work is that of Mach, 

 'Die Mechanik und ihre Entwickelung, ' 

 1895, of which there is an English trans- 

 lation. This'author carefully analyzes the 

 conceptions upon which the mechanics are 

 based, and shows how those conceptions 

 have varied from time to time. Especially 

 satisfactory is his chapter on the analytical 

 mechanics in which he shows how far New- 

 ton developed the subject, using as his 

 fundamental conception the attraction be- 

 tween two points. His method was purely 

 geometrical and synthetic. He then points 

 out how Euler and Maclaurin introduced 

 the idea of resolving each such force into 

 forces along three coordinate axes; and 

 further, how finally Lagrange, by his in- 

 troduction of the ideas of the calculus of 

 variations, completed the structure. The 

 succession of ideas here outlined is admir- 

 ably treated by our author. 



The historical works of Todhunter are of 

 great value. His method is simple, direct, 



