82 ESSAYS AND OBSERVATIONS 



moft bodies, when further burned to aflies, 

 affume a grey or whitifli colour ? 



QuERr XX. Since the caufe of blacknefs- 

 in bodies is the fmalhiefs of their tranfparent 

 parts, which renders them incapable of re- 

 flecting any colour ; how can black bodies, 

 folid or fluid, be at the fame time opaque ? 

 Can light be finally ftifled by the refractive 

 powers of the particles alone ? or, ought it not 

 rather to make its way thro' the body, if 

 there be no reflexion, without any fenlible 

 lofs, altho* the feveral rays might iflue in 

 various directions ? And, may it not be de- 

 manded, in like manner, concerning all co- 

 loured opaque bodies, How all forts of light 

 can be ftifled and fl:opt within a body, whofe 

 internal parts are fitted to refleCt only one or 

 two colours, and tranfmit all the reft ? 



QuER. XXI. If the parts and pores of 

 pellucid bodies be much iefs than the leaft 

 interval between the fits of reflexion and 

 tranfmiffion ; k is plain, that rays of light, 

 entering a part or pore in a fit of tranfmiffion, 

 will not be reflected at its back furface : and 

 thus it may be underfl;ood, how all rays that 

 enter the firft furface of a tranfparent body 

 continue to be tranfmitted thro' its fubftance 



to 



