cade S ee 
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 gas. 
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 BerrHo.ier, 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 
Vou. VIII. P. Il. Uu acid, 
