156 THE POPULAR SCIENCE MONTHLY. 



suppose otherwise, is to ascribe to him a rashness which no disciplined 

 man of science could be guilty of. 



See, then, the critical capacity variously exhibited in the space of 

 a single sentence. The reviewer, quite erroneously, thinks that ob- 

 servations unguided by hypotheses suffice for physical discoveries. 

 He seems unaware that, on a priori grounds, the law of the inverse 

 square had been suspected as the law of some cosmical force, before 

 Newton. He asserts, without warrant, that no such a priori concep- 

 tion preceded, in Newton's mind, his observations and calculations. 

 He confounds the law of variation of a force with the existence of a 

 force varying according to that law. And he concludes that Newton 

 could have had no a priori conception of the law of variation, because 

 he did not assert the existence of a force varying according to this law 

 in defiance of the evidence as then presented to him ! 



Now that I have analyzed, with these results, the first of his criti- 

 cisms, the reader will neither expect me to waste time in similarly deal- 

 ing with the rest seriatim^ nor will he wish to have his own time occu- 

 pied in following the analysis. To the evidence thus furnished of the 

 reviewer's fitness for the task he undertakes, it will suffice if I add an 

 illustration or two of the animus which leads him to make grave im- 

 putations on trivial grounds, and to ignore the evidence which contra- 

 dicts his interpretations. 



Because I have spoken of a balanced system, like that formed by 

 the sun and planets, as having the " peculiarity, that though the con- 

 stituents of the system have relative movements, the system, as a 

 whole, has no movement," he unhesitatingly assumes me to be unaware 

 that, in a system of bodies whose movements are not balanced, it is 

 equally true that the centre of gravity remains constant. Ignorance 

 of a general principle in dynamics is alleged against me solely because 

 of this colloquial use of the word " peculiarity," where I should have 

 used a word (and there is no word perfectly fit) free from the implica- 

 tion of exclusiveness. If the reviewer were to assert that arrogance is 

 a " peculiarity " of critics ; and if I were thereupon to charge him 

 with entire ignorance of mankind, many of w^hom besides critics are 

 arrogant, he would rightly say that my conclusion was a very large 

 one to draw from so small a premise. 



To tliis example of strained inference I will join an example of 

 w^hat seems like deliberate misconstruction. From one of my essays 

 (not among the works he professes to deal with) the reviewer, to 

 strengthen his attack, brings a strange mistake ; which, even without 

 inquiry, any fair-minded reader would see must be an oversight. A 

 statement true of a single body acted on by a tractive force, I have in- 

 advertently pluralized ; being so possessed by another aspect of the 

 question, as to overlook the obvious fact that with a plurality of 

 bodies the statement became untrue. Not only, however, does the re- 

 viewer ignore various evidences furnished by the works before him, 



