ON THE NITUEK OF OXIMURIATIC A.CI9* 



295 



taVen an incorrect view of hig brother*s opinion, which, he 



adds, is a thet)ry, not an hypothesis. 



The tree si^nilicalion i^enerally ^iven to the word theory General use of 



in chemical languao;e is so well imdcrstood, that I did not ^'^* ^of<i the- 



, , , '^ . . ... ory. 



•uppose it could Iiave given rise to any ambiguity requiring 



to be poinl«d out. Theory, strictly understood, implies, no 

 doubt, a principle established by just iiiduction froiu indivi- 

 dual fact€, and applied to the explanation of phenomena; 

 while in an hypothesis a principle is as8u;iied, whence 

 phenomena are attem[)t(;d to be explained. But there 

 is an intermediate kind of reasoning or speculation, in 

 which there is partly generalization, partly hypothetical, 

 assumption — a principle being professedly inferred by in- 

 duction, but requiring the aid of hypothesis to apjily it to 

 all the phenomena connected with the subject. To this the 

 terms opinion, theory, and hypothesis are often indiscrimi- 

 nately applied ; and theory in chemical language has more 

 frequently this signilication than any other. The successive 

 revolutions in chemistry would lead us to doubt indeed if it 

 can be often justly used in its more strict sense, implying a 

 perlect induction, the certainty of which subsequent disco- 

 veries cannot change. The theory of Stahl, as it has been 

 named, which at one period commanded universal assent, 

 was quickly subverted. Much of the theory of Lavoisier, 

 ample and conclusive as the evidence appeared to be on „ ., r 



which it is founded, must, if late speculations be just, share S 



the same fate. And even those more partial inductions, 

 which appeared to have the utmost certainty, are many of 

 them, It now appears, doubtful. To a philosophic inquirer 

 this may perhaps suggest some caution in applying the 

 term theory in its strict signilication, and it may guard him 

 against the most common of liH ^rrours — an undue confi- 

 dence in our speculations, and thp belief that the opinions 

 of our day are demonstrated truths. 



Mr. J. Davy's mistake, and which I should have obviated 

 in my former paper, had I supposed any one attending par- Source of Mr. 

 ticularly to the subject, and accustomed to scientitic deduc- t^g.^'^ 

 tion, could have fallen into it, and had 1 not wished to avoid 

 holding out unnecessarily Mr. H. Davy's opinion as purely 



hypothetical. 



