I Co Mr. Dehval on the Caiije of the 



" bodies, appear of one and the fame colour, 

 " in all pofitions of the eye, though this I cannot 

 ** yet affirm by experience." * 



And he thus exprefifes himfelf, relative to the 

 opacity of glafs wedges filled with red, and blue 

 liquors, when viewed conjointly. *' This Mr. 

 ** Hook tried cafually with glafs wedges filled 

 ** with red and blue liquors, and was furprized 

 " at the unexpefled event, the reafon of it being 

 *' then unknown ; which makes me truft the 

 *' more to his experiment, though I have not 

 «« tried it myfelf." f 



We find, at the clofe of the Optics, a pafTage 

 relative to the infledlions of the rays of light 

 and the colours made thereby, which feems 

 capable of being extended to all thofe obferva- 

 tions, which the illuftrious author had left im- 

 perfed, or had not profecuted with that eminent 

 degree of induftry and circumfpeftion, which are 

 generally confpicuous in his inquiries. It is as 

 follows: "When I made the foregoing obfer- 

 *' vations, I dcfigned to repeat mofl: of them 

 " with more care and exaiftnefs; but I was then 

 " interrupted, and cannot now think of taking 

 " thefe into farther confideration." % 



Sir Ifaac Newton was of opinion, that all 

 Coloured Matter reflects the rays of light, fomc 



♦ Newton. Opt, L. I. Part. II. Prop. X. Probl. V. 

 t lb. X lb. L. III. ad calc. 



bodies 



