264 Mr. "Delaval en the Cauje of the 



refledls the incident rays equally, and regularly, 

 as a mirrour : but, when the furface is rough, and 

 unequal, or divided into minute particles, it re- 

 fle6ts the incident rays irregularly, and promifcu- 

 oufly, in different direftions, and confequently 

 appears white. 



As the furfaces of pellucid colourlefs nnedia are 

 difpofed indifcriminately to rcfled all the rays of 

 light J fo white opake fubftances, which are com- 

 pounded of pellucid colourlefs media, retain the 

 fame difpofition, which is indifferent to all the 

 forts of rays. 



It has been already (hewn, throughout the 

 courfe of this inquiry, that coloured matter does 

 not refleft any light ; but, that reflexive media ad 

 indifcriminately on all the different rays. It does 

 not appear from the optical phenomena, which 

 have hitherto been obferved, that nature affords 

 any kind of matter endued with a power of reflett- 

 \T\o one fort of rays, more copioufly than tlie 

 other forts. Confequently, no leBedjve fubftances 

 are capable of feparating the differently refrangi- 

 ble rays, and thereby producing colours. 



There are feveral experiments, and obfcrva- 

 tions, in S> Ifaac Newton's Optics, from which 

 it mi^ht have been inferred, that coloured light 

 is not reflefted from coloured matter, but from 

 white or colourlefs matter only. 



Although that great philofopher fuppofes, that 

 ^11 colQured bodies reflect the rays of their own 



. colours. 



