BETWEEN MURIATIC ACID AND CHLORINE. 337 



gas, could be regarded with Davy, as resulting from a metallic 

 analysis of hydrochloric acid ; or it might be derived from the 

 combined water of muriatic acid, of which the oxygen became 

 fixed in the muriate of tin. When chlorine also at high heats 

 was made to act on earths or common metallic oxides, the 

 evolved oxygen, could be referred with equal probability either 

 to the solid or to the eras. 



And though we ignite by the strongest voltaic power, char- 

 coal or other combustibles in chlorine, still we shall not be 

 able to convert it into muriatic acid gas, for want of the essen- 

 tial constituent water ; no more than we can, without the same 

 water, obtain oil of vitriol. Present water to chlorine, then 

 light alone will separate its oxygen, and leave muriatic acid. 

 Such, indeed, is the affinity existing between the muriatic 

 acid basis and water, that those muriates which of themselves 

 resist decomposition at a red heat, when exposed at that tem- 

 perature to the vapour of water, are speedily resolved into ga- 

 seous muriatic acid, and their peculiar bases. 



By restoring the theory of Lavoisier and Berthollet, we 

 get rid of those mysterious and almost incomprehensible trans- 

 formations which a drop of water has been lately conceived to 

 produce on some of the muriates. Dried sea-salt, for example, 

 when viewed as a compound of chlorine and sodium, is no 

 sooner moistened, than a portion of water resolves itself into 

 oxygen and hydrogen, whence result soda and hydrochloric 

 acid, and a solution of muriate of soda. Expel the drop of 

 water, we have a chloride of sodium once more ; and we may 

 repeat this invisible change for an indefinite number of times 

 by the addition or subtraction of a little moisture. Thus we 

 must consider dry salt and moist salt to be bodies widely and 

 essentially different, the former containing neither alkali nOr 



Vol. VIII. P. II. U u acid 



