248 Mr. Delaval on the Cauje of the 



and by a fubfcquent tranfmifTion through the 

 pellucid glafs. 



From all the experiments which I have here 

 adduced, it uniformly appears, that no Coloured 

 Light is refledted from the anterior furfaces of 

 Opake, Semipellucid, or Tranfparent Coloured 

 Bodies. For, in thefe, the light is reflefted by 

 the fuperficies which intercedes the tranfparent 

 part of the medium, and the fubftance which is 

 behind it: and the light, thus refleifled, is tranf- 

 mitted back, through the tranfparent part of the 

 medium, which intervenes between the refledlive 

 furface, and the anterior furface. 



In thefe refpefts, the Coloured Media, which 

 have been examined throughout the courfe of 

 this inquiry, agree with the plates of glafs obferved 

 by the Duke de Chaulnes. 



If the experiments, which have been made 

 with thin Tranfparent Colourlefs Subftances, 

 and thofe which have been performed with 

 Coloured Media, be jointly confidered, it wijl 

 appear that the effe£ts, which Sir Ifaac Newton 

 has attributed to Refleded Light, fliould have 

 been applied to Tranfmitted Light. And the 

 obfervatiorj of this great philofopher, relative 

 to the connexion between the colours of natural 

 bodies, and the fize and denfity of their particles, 

 if thus modified, will coincide with his own 

 experiments, and all the others v/hich have been 

 made fubfequent to them. 



