364 Dr. Herschel's Reviewer reviewed. 



If the reviewer still continues his negative to those ques- 

 tions, his notions of knowledge and science must be of 

 some very peculiar conformation. 



Further, in The Retrospect, pages 23 and 24, it is said : 

 *' Doctor Herschel seems to have confined his study of the 

 phasnomena of light almost entirely to the works of New- 

 ton." And was not his doing so, in this paper, highly 

 proper ; when he was, by experiments, investigating tlie 

 cause of (he coloured rings discovered by Newton ? It is 

 immediately added, " not thinking it worth his while to 

 inquire whether the last hundred years had produced any 

 thing deserving his attention ; and taking it also for granted, 

 that little or nothing was known before him," &c. This, 

 and some other moFsels of the like sorr, which are passed 

 over, nearly rival in elegance the rev\e\ver's J uvi urn. Sec. 

 But as nothing whatever is to be found in the essay that 

 can show what the author takes for granted, we are quite 

 at a loss in conjecturing who has let the reviewer into that 

 secret. 



Asain, in The Retrospect, p. 24, line 6, it is said, " But, 

 in fact, the colours of those plates were by no means the 

 discovery of Newton; they have been described with great 

 accuracy by the ingenious, but too much neglected, Doctor 

 Hook." Here the reviewer discovers a Iaudal)le sympathy 

 and concern for departed merit; but we find nothing in the 

 essay which could induce him thus to conjure up the shade 

 of that philosopher. The tendency of the passage last quo- 

 ted, though it cannot be supposed intentional, is to fasten 

 a chartre of ignorance on the author -, as if he had ever 

 maintained that the phaenomena of these coloured thin 

 plates were the discoveries of Newtou. The author in his 

 essay has never alleged any such thing. He has said, in- 

 deed, and trulv^ both in his title and elsewhere, that the 

 coloured rings were discovered by Newton. This it is well 

 known Newton did by making use of prisms, and at last 

 object-elasses, brought into contact. See Newton's Opticks, 

 book iL, part I. observations 2, 3, 4. 



A""ain, in Retrospect, page 24^ we find as follows ; " The 

 experiment made by strewing particles of hair-powder in a 

 sunbeam, is still more unconnected with the question." 

 The most evident and close connection of that experiment 

 with the subject will be best seen by Doctor Herschel's 

 own words ; when it is considered that he was then bring- 

 in"" his proofs from experiment to bear against the existence 

 of the fits of easy reflection and easy transmission of light. 



As a reason for pronouncing that experiment uncour 



iiectcd 



