174 ^f' T>elavalon the Caufe of the 



When a lighted candle is placed near one of 

 thefe coloured plates, the flame is reflcded by 

 the mediunn, which is diffufed over the anterior 

 furface of the plate. The innage, thus refleded, 

 refembles the flame, in fize, and colour. For, it 

 is fcarce fenfibly diminiflied, and // is not in the 

 leafi tinged by the coloured glafs. 



If the plate be not fo intenfely coloured, or 

 fo maflTy, as to hinder the tranfmiflion of the light 

 of the candle, there appears a fecondary image 

 of the flame, which is refie6led by the medium, 

 contiguous to the farther furface of the glafs. 

 And as the light, thus refleded, pafles back 

 through the coloured glafs, it is vividly tinged 

 by it. 



When the glafs, ufed in this experiment is 

 green, the fecondary image of the flame aflumes 

 a bright green colour. When glaflTes of other 

 colours are ufed, the colour of the fecondary 

 image is always the fame, as that of the glafs. 



The fecondary image is Icfs, than that which 

 is refleded from the anterior furface. This di- 

 minution is occafioned by the lofs of that part of 

 the light, which is abforbed, in pafllng through 

 the coloured glafs. For, whenever ary medium 

 tranfmits one fort of rays, more copioufly than 

 the refl, it fl:ops a great part of the oppofitely 

 coloured rays. And much more light is lofl:, in 

 its pafllige through coloured, than through pellu- 

 cid colourlefs, fubfliances. 



In 



