Chemical Properties attributed to Light. J'j 



tion to be exposed to the action of the current of hot 

 vapour that arose from the burning candle, all those 

 parts which had been so wetted were tinged with the 

 same beautiful purple colour. 



This colour, which was uncommonly brilliant, passed 

 quite through the ribbon ; and I found the stain to be 

 perfectly indelible. I endeavoured to wash it out ; but 

 nothing I applied to it appeared in the smallest degree 

 to diminish its lustre. The hue was not uniform, but 

 varied from a light crimson to a very deep purple, 

 approaching to a reddish brown. 



I searched but in vain for traces of revived gold in 

 its reguline form and colour ; but, though I could not 

 perceive that the ribbon was gilded, it had all the 

 appearance of being covered with a thin coating of the 

 most beautiful purple enamel, which in the sun had a 

 degree of brilliancy that was sometimes quite dazzling. 



Experiment No. 2. — A piece of the ribbon which 

 had been wetted with the aqueous solution of the oxide 

 was carefully dried in a dark closet, and was then 

 exposed dry over the flame of a burning wax candle. 

 The part of the ribbon which had been wetted with the 

 solution (and which on drying had acquired a faint 

 yellow colour) was tinged of the same bright purple 

 colour as was produced in the last-mentioned experi- 

 ment, when the ribbon was exposed wet to the action 

 of the heat.* 



Experiment No. 3. — A piece of the ribbon which 

 had been wetted with the solution, and dried in the 

 dark, was now wetted with distilled water and exposed 

 wet to the action of the ascending current of hot 



* We shall hereafter find reason to conclude that the success of this experi- 

 ment, or the appearance of the purple tinge, was owing to the watery vapour 

 or steam which existed in the hot current of vapour that ascended from the 

 flame of the candle. 



