74 ESSAYS AND OBSERVATIONS 



Sir I/aac Newtofi*, that the violet and blue- 

 making rays are refiedted more abundantly 

 than the reft, by the finer vapours diffufed 

 tliro' the atmofphere whofe parts are not 

 big enough to give them the appearance of 

 viiible opaque clouds? Do not thofe who 

 fay -f-, that the ethereal blue proceeds from 

 the mixture of the fun's white light refled- 

 ed faintly by the atmofphere with the perfedt 

 blacknefs of the celeftial fpace behind, re- 

 vive, without any neceflity, the antient con- 

 fufed notion, that all colours may be formed 

 by certain compofitions of light and fliade ? 

 Altho' the atmofphere refleds more blue ray& 

 than what go to the formation of perfed: 

 white, it is eafy to conceive how coloured 

 bodies, illuminated by it, may not be fenfi- 

 bly tindured with blue. Let us fuppofe, 

 that the atmofphere refleds - more of blue 

 rays than of the other colours, and that ver- 

 milion refleds ^f of the red rays incident 

 upon it, and -~ of every other colour; 

 then, it is clear, that the red rays, refleded 

 by the vermilion, will ftill exceed the blue 

 refleded by it, as 1 9 exceeds i + ^ : fo 



that 



* Opt. book 2. part 3. prop. 7. 



•f Nature difplayed, vol. iv. And Mujchen. Phyf. § 1403, 



