418 HISTORY OF OPTICS. 



vations to the Royal Society, as "a new property of 

 light not mentioned by any optical writer before ;" 

 by which we see that he had not heard of Gri- 

 maldi's experiments. Newton, in his Opticks, treats 

 of the same phenomena, which he ascribes to the 

 inflexion of the rays of light. He asks (Qu. 3,) 

 " Are not the rays of light, in passing by the edges 

 and sides of bodies, bent several times backward 

 and forward with a motion like that of an eel? 

 And do not the three fringes of coloured light in 

 shadows arise from three such bendings?" It is 

 remarkable that Newton should not have noticed, 

 that it is impossible, in this way, to account for the 

 facts, or even to express their laws ; since the light 

 which produces the fringes must, on this theory, be 

 propagated, even after it leaves the neighbourhood 

 of the opake body, in curves, and not in straight 

 lines. Accordingly, all who have taken up Newton's 

 notion of inflexion, have inevitably failed in giving 

 anything like an intelligible and coherent character 

 to these phenomena. This is, for example, the case 

 with Mr. (now Lord) Brougham's attempts in the 

 Philosophical Transactions for 1796. The same 

 may be said of other experimenters, as Mairan 2 and 

 Du Four 3 , who attempted to explain the facts by 

 supposing an atmosphere about the opake body. 

 Several authors, as Maraldi 4 , and Comparetti 5 , re- 



2 Ac. Par. 1738. 3 Memoires Presents, vol. v. 4 Ac.Par.1723. 

 5 Observations Opticce de Luce Inflexa et Colorilus. Padua. 



1787- 



