( 391 ) 



a water wlilch, falling down, produced at 

 the bottom a tolerable quantity of liquor. 

 1 found its weight 77^ grains. It had the 

 ufual tafte of the muriatic acid ; and the 

 prefence of this and no other was confirmed 

 by the re-agents I had applied to the other 

 liquor. It was now, therefore, proved that 

 this acid, united to water, was really contain- 

 ed in the volcanic glafs. The appearance of 

 white vapours in the glafs receiver was thus 

 explained ; as they proceeded from the 

 warer mixed with the muriatic acid, it 

 being well known that this acid, when it 

 comes in conta<fl with any humidity, pro- 

 duces fuch vapours. The water reduced 

 to vapour was condenfed by the cold of the 

 receiver, and fell to the bottom. ; and the 

 acid in queftion, from its great affinity with 

 it, was abforbed by it. 



But is this fadt confined to this particular 

 fpecies of volcanic produd:, or does it ex- 

 tend to others ? To afcertain this was of 

 fome importance. I, therefore, made the 

 fame experiments on the black glafs of the 

 C c 4 fame 



