BEGINNINGS OF MODERN CHEMISTRY 



gen, baryta, and chlorine, the last of far greater im- 

 portance, at least commercially, than the real object of 

 his search. In speaking of the experiment in which 

 the discovery was made he says : 



" When marine (hydrochloric) acid stood over man- 

 ganese in the cold it acquired a dark reddish-brown 

 color. As manganese does not give any colorless solu- 

 tion without uniting with phlogiston [probably meaning 

 hydrogen], it follows that marine acid can dissolve it 

 without this principle. But such a solution has a blue 

 or red color. The color is here more brown than red, 

 the reason being that the very finest portions of the 

 manganese, which do not sink so easily, swim in the 

 red solution ; for without these fine particles the solu- 

 tion is red, and red mixed with black is brown. The 

 manganese has here attached itself so loosely to acidum 

 salts that the water can precipitate it, and this precipi- 

 tate behaves like ordinary manganese. When, now, 

 the mixture of manganese and spiritus salts was set to 

 digest, there arose an effervescence and smell of aqua 

 regis."* 



The "effervescence" he refers to was chlorine, which 

 he proceeded to confine in a suitable vessel and ex- 

 amine more fully. He described it as having a " quite 

 characteristically suffocating smell," which was very 

 offensive. He very soon noted the decolorizing or 

 bleaching effects of this new product, finding that it 

 decolorized flowers, vegetables, and many other sub- 

 stances. 



Commercially this discovery of chlorine was of enor- 

 mous importance, and the practical application of this 



