334 COLORIFICATLON IN GENERAL. 



which, with pure, colorless, invisible light/- 

 colorless and invisible light becomes light, visi- 

 ble and colored. We behold colored light 

 evolved, in the most obscure nights, from ani- 

 mals of the feline race in general, from fish, 

 from the glow worm, from pyrophori, 

 from the Bolognian stone, and from different 

 kinds of crystals and of diamonds. We see 

 colored light perpetually radiating from bodies 

 in a state of combustion : the quality of the 

 color seems altogether to depend on the nature 

 of the materials of which the base is composed, 

 subservient to that process ; different kinds of 

 coal and of peat, always produce a peculiarity 

 in the color of the flame. The same variety in 

 the color of the flame subsists in our lamps and 

 candles, whether they are made of oil, of tal- 

 lowy or of wax ; and it may also be observed, 

 that by some experiments that were made on the 

 tallow of an old woman, who had been condemn- 

 ed to suffer death as a malefactress, it was found 

 that the candles which were made from it, gave 

 out a flame of a beautiful blue color. Spirit of 

 wine imparts a blue, the green calx of copper, 

 a green, and the white calx of zinc, a flame 

 as white and as bright as it is possible to con- 

 ceive ; while, on the contrary, the smoke or 

 black flame which issues out of many furnaces, 

 is often as black as jet. This combined light 

 is often proved to exist in the atmosphere, by 



