90 ON THE CONVOLUTIONS OF STRATA, 



servation in Sir George Mackenzie's work, it recalled to 

 me what I had seen in Sicily, where the Cyclopian Islands, at 



the 



" and it continues to form until the substance is deprived of its ingredients ; but 

 " when a solid body prevents its escape, the particles first formed acquire a de- 

 " gree of condensation proportional to the resistance which they experience, 

 " and they oppose in their turn the same resistance to the formation of other 

 " particles. Under such circumstances, therefore, if the heat be increased, it 

 " produces other combinations of the fixed air with the calcareous earth, as in 

 " the experiments of Sir James Hail. But, under water % which the particles 

 " of that gass can easily penetrate, in which, collecting in bubbles, they will 

 " rise rapidly, on account of their inferior specific gravity, there can be no im- 

 " pediment to their formation, any more than that of the aqueous vapour in wa- 

 " ter, under the pressure of the atmosphere, when the heat is sufficiently in- 

 " tense." 



When M. de Luc says, that in my experiments a solid body preventing the 

 escape of the fixed air, " the particles first formed acquire a degree of condensa- 

 " tion proportional to the resistance which they experience, , '' he must conceive, 

 that during the first application of heat, some fixed air has separated from the 

 lime, and has accumulated in the cavity left in the barrels. But if he will look 

 again into my paper, he will find that I had foreseen this inconvenience, and 

 had guarded against it ; that being under the necessity of leaving some cavity, 

 in order to allow for the liquid expansion of the fusible metal, I introduced some 

 water into the barrel, which assuming the gaseous form, and reacting with great 

 power, before the heat had risen to the calcining point, effectually prevented the 

 separation of any fixed air. And the same thing would happen at the bottom of 

 a sea that was deep enough. In some of my experiments, made with a compres- 

 sing force equal to 171 atmospheres, equal to 5693 feet, or about a mile of sea, 

 the carbonate bore the heat of melting gold without calcination, and entered in- 

 to fusion. Now, it is obvious, that the same result must take place at the bottom 

 of a sea of this depth, and that a shell lying on its bottom, if met by a lava 

 whose heat was equal to that of melting gold, would enter into fusion, and no 

 fixed air would be separated in the form of gas. M. de Luc's objection, there- 

 fore, which is founded on the levity of the substance in that gaseous form, must 

 fall to the ground. 



In those experiments which I have made, with a compressing force applied by 

 means of a known and regulated weight, the carbonate has been placed exactly 



in 



