164 THE POPULAR SCIENCE MONTHLY. 



its study is regarded as inferior in intellectual results to that of lan- 

 guage or philosophy. It can not be denied, however, that the study 

 of physical science gives a certain definiteness to our modes of think- 

 ing, even if it will not be granted that it affords a better method of 

 intellectual training than philological study. It supplies a tonic which 

 minds much accustomed, from the exclusive study of language, to 

 take things for granted and to look no further than the grammar and 

 dictionary stand much in need of, and also corrects a certain credu- 

 lity and superstition which is rampant, even in our time, and to which 

 it is well to devote a few words in connection with the subject of 

 scientific training. There is a strong undercurrent of superstition 

 and belief in supersensible or wonderful and not-to-be-explained mar- 

 vels which makes its way beneath the crust of society. Occasionally 

 it bursts forth in so-called manifestations of spiritualism and animal 

 magnetism, or belief in mesmerism and clairvoyance. There is hardly 

 a family of which some member has not applied to a clairvoyant for 

 relief in diseases which the regular practitioner has failed to treat 

 successfully. A literary education does not cope successfully with 

 the insidious advances of this form of ignorance ; for the very ele- 

 ment of education which can do so is not generally cultivated among 

 even so-called liberally educated persons. This lost element is the 

 spirit of investigation. The students who come to a physical labora- 

 tory for the first time can be rapidly classified into three classes : 1. 

 Those who can reason from A to B over what may be termed a 

 straight line with considerable ease. 2. Those who naturally reverse 

 their process of reasoning and test the way from B to A; this is a 

 rarer class of minds. Copernicus was unable to explain the motions 

 of the planets by supposing that all the visible stars revolved around 

 the earth ; he reversed his process of reasoning, and explained the 

 facts by supposing the earth to turn and the stars to remain at rest. 

 Kant, in his " Critique of Pure Reason," speaks of the revolution which 

 he had brought about in philosophy, and likens it to the logical process 

 which led Copernicus to his discovery. "Hitherto," he says, "it had 

 been assumed that all our knowledge must regulate itself according to 

 the objects ; but all attempts to make anything out of them a priori, 

 through notions whereby our knowledge might be enlarged, proved, 

 under this supposition, abortive. Let us, then, try for once whether 

 we do not succeed better with the problems of metaphysics, by assum- 

 ing that the objects must regulate themselves according to our knowl- 

 edge, a mode of viewing the subject which accords so much better with 

 the desired possibility of a knowledge of them a priori, which must 

 decide something concerning objects before they are given us." In 

 practical matters this process of reversals is often exemplified ; the 

 inventor of the sewing-machine finds that his needle will not work with 

 the eye at one end, and accordingly reverses its position and is suc- 

 cessful. 3. The third class comprises those who may be said to think 



