2o On Volcanos and Earthquakes. 



between the two fluids, and upon their relative specific 

 gravity. 



4th. That any particular effect of pressure upon air may 

 take place, deep in the ocean, must of course depend upon 

 the fact that air is conveyed to the region supposed. 



5th. No cause is obvious, that can produce such an effect; 

 the extensive contact of air and water, however often re- 

 peated, can do no more than saturate water with air, at the 

 particular temperature and pressure. 



6th. In this condition, and upon the surface of the globe, 

 the water and the air form, apparently, a homogeneous flu- 

 id, and should this fluid descend to the greatest depth, and 

 be subjected to ever so many miles of pressure, it is not per- 

 ceived that the air and water would probably separate, or 

 undergo any other change than a diminution of volume, as 

 proved by Mr. Perkins' experiment on the compressibihty of 

 water. 



7th. Could air be forced down through and beneath a su- 

 perincumbent ocean, of the depth supposed, then it would 

 be in a suitable condition to receive the efiect of the pres- 

 sure ; but air, already united to water at or near the surface, 

 has already become a fluid by the union, (or a constituent 

 of a fluid,) and will probably undergo no other change than 

 a mere fluid undergoes. 



8th. Is it physically possible, that any aerial body should 

 be subjected to such a pressure, as to acquire a specific grav- 

 ity greater than that of water, and still retain its aerial form? 

 Would not the supposed approximation of its particles neces- 

 sarily cause it to become a fluid ; and is it not physically pos- 

 sible that by increased pressure it may become even a solid ? 



Answer to the Objections. 



No. 1 and 2. Experiments made in Paris, prove that air 

 may be condensed above the density of water, without losing 

 its elastic or gaseous properties ; the point at which it is 

 condensed into a liquid being beyond that density. 



No. 3. Why should it not form a stratum under water, its 

 density being greater, and the two fluids having combined as 

 far as their affinity goes ? 



No. 4 and 5. True, that the air should be conveyed to the 

 lowest regions of the ocean, is a consequence of its whole 

 mass being saturated with it. 



No. 6 and 7. That the air should separate from water sat- 



