RESIDUAL PHENOMENA. 105 



But the examination of residual phenomena may also help to free 

 investigators from that tyranny which is exerted by a number of con- 

 cordant results, all seemingly pointing to but one conclusion. 



If experiment after experiment points to one conclusion, and if all, 

 with the exception of perhaps a single residual fact, is in favor of this 

 conclusion, it is hard to resist the temptation to ignore that fact, and 

 adopt what, but for it, is apparently the true conclusion. But this 

 method is not the scientific method. The fact must be examined. It 

 may be that the outstanding fact is finally reduced within the sphere 

 of the previously adopted hypothesis, or it may be that a new hypothe- 

 sis is suggested which explains this and all the other phenomena. 



The great Swedish chemist Berzelius carefully examined the prop- 

 erties of the compounds of a newly discovered element ; he determined 

 the chemical and physical characteristics of this element, to which he 

 gave the name of Vanadium. The facts ascertained by the experiments 

 of Berzelius formed a concordant series ; so far as these experiments 

 extended, everything appeared to be in keeping with the conclusions 

 arrived at by him. But it was afterward noticed that the crystalline 

 form of certain compounds of the metal vanadium was different from 

 that required by the commonly accepted and, as it appeared, well-estab- 

 lished theories concerning the connection between crystalline form and 

 chemical structure. The examination, by Roscoe, of the residual phe- 

 nomena presented by the crystalline forms of the vanadium compounds 

 led to the astonishing discovery that the so-called metallic vanadium 

 of Berzelius was really not an elementary body, but a compound of the 

 true metal vanadium with oxygen. This peculiar oxide presents most 

 of the physical properties of a metal ; indeed, so metal-like is this 

 oxide that the presence in it of oxygen was entirely overlooked, even 

 by so careful a worker as Berzelius. 



The researches of Roscoe threw a new light upon the chemical his- 

 tory of vanadium, and at the same time confirmed in a marked manner 

 the law connecting chemical structure with crystalline form. 



But, lastly, the study of residual phenomena may aid in freeing our 

 minds from that fascinating, but surely erroneous, idea which a mere 

 superficial acquaintance with natural science tends so much to strength- 

 en, viz., that Nature is, and indeed must be, extremely simple. 



The simplicity of Nature is a favorite theme with a certain class of 

 would-be philosophers : it is a doctrine easily accepted, but a doctrine 

 which has led to pernicious results. 



Extreme instances of the overruling power of this idea may be found 

 in the fascination exerted over minds, even of the highest order, by nu- 

 merical analogies, that are really baseless. The seven colors of the 

 spectrum were supposed, even by the great master himself, to have 

 some mysterious connection with the seven tones of music. The num- 

 ber of the satellites of Jupiter added to the single satellite of the earth 

 leaves but one satellite for Saturn, if the perfect number six is to be 



