DISCOVERIES BECOME FAMILIAR. 437 



feel it easier to bear with injustice, than to struggle for 

 redress. And as to considerations of pecuniary interest, 

 they are of no value in my estimation. Besides which, 

 ,my future depends on the encouragement that the public 

 may be inclined to grant me, and not at all on that of 

 Mr. Cavendish or of his friends." 



Ought I to fear, that I have attached too much im- 

 portance to the theory that Watt imagined for explain- 

 ing Priestley's experiments ? I think not. Those who 

 would refuse a rational consent to this theory, because it 

 now seems the inevitable result of facts, must forget that 

 the finest discoveries achieved by the human mind have 

 been, above all, remarkable for their simplicity. What 

 did Newton * himself do, when, repeating an experiment 

 that had been known already for fifteen centuries, he dis- 

 covered white light? He gave so natural an interpreta- 

 tion of this experiment, that it now seems impossible to 

 offer any other ; he says — " All that is obtained, by any 

 proceeding whatever, from a pencil of white light, must 

 have been contained in it in a state of mixture. The 

 glass prism possesses no creative property. If the paral- 



* This is barely in point; some of the phenomena of colours were 

 certainly known before the advent of Newton, but that jji'inceps liliihs- 

 ophorum formed the prismatic spectrum itself, by which the spaces 

 occupied by the successive colours were accm-atel}- defined, the 

 colours submitted to a similar analysis, and the white light re-formed; 

 thus ascertaining and proving that light, instead of being homoge- 

 neous as had been supposed, was actually a heterogeneous mixture 

 of differently refrangible rays. Nor do we quite quadrate with the 

 lengthy discussion before us, since we do not consider the case — in re 

 the beautiful composition of water — to be conclusively established. 

 To those readers who are interested in so crucial a point in scientific 

 history, we recommend a perusal of Vernon Harcourt's remarkable 

 address to the British Association at Birmingham, in 1839; it being 

 alike free from reckless assertion, and that hot nationality which 

 warps judgment. — Translator. 



