244 ■^^''' "Ddaval on the Cauje of the 



The violet rays are tranfmitted through th(t 

 glafs, and, therefore, it appears vividly tinged 

 with a violet colour, when looked through. 



In proportion as the tranfparency of this red 

 glafs is impaired, the tranfmitted colour recedes 

 from red, till it becomes violet: according to 

 the law which all Tranfparent Bodies obferve, 

 when Opake Particles are introduced into, or 

 formed in them, fo as to render them femi- 

 pellucid. 



This experiment manifefts the flrong refleftive 

 power, with which the particles of gold are 

 endued, according to their fpecific gravity. 



In this kind of glafs, and in all other Semi- 

 pellucid, as well as Opake, Coloured Subftances, 

 colours are refiedled from White, or Colourlefs 

 Particles only, and are tranfmitted through the 

 Tranfparent Parts of the Media. 



It is not neceffary to extend this fubjeiSV, by 

 a defcription of Semipellucid Liquors, as they 

 aft according to the fame laws, and afford the 

 fame appearances, as the folid media, which have 

 been already inftanced. 



In the preceding experiments, I have preferred 

 the ufe of femipellucid glaflcs, becaufe they are 

 not apt to be decompofed, or fuffer any variation 

 in their texture -, and therefore are difpofed, con- 

 Itantly, and equably, to exhibit the fame colours. 



The coloured light, whichis tranfmitted througli 

 Semipellucid Subftances, paflcs through the in- 

 tervals 



