On Volcanos and EarthquaJtes, 13 



But for reasons to be explained in the course of this arti- 

 cle, we will assume that the air is only eight hundred times 

 lighter than sea water, or - - - :: 0,00125 : 1. 



This being granted : let us sup- 

 pose that a bell ABC, suspended by 

 a metallic chain, and full of atmos- 

 pheric air, is plunged into the ocean; 

 the air contained in it will be com- 

 pressed more and more as it descends, 

 and consequently its density will be 

 increased in proportion to the depth 

 it penetrates. This condensation is 

 here represented, at first by the line 

 BC, at the moment of its immersion, 

 Cthen by the lines DE, FG, HI, &c. 



The following table will show the ratio of the condensation 

 compared with the depth of the immersion. 



From this table it appears that the point at which the 

 density of the atmospheric air would be exactly equal to 1 , 

 or equal to the density of sea water, is to be found between 

 16,352 and 32,736 feet immersion in the sea. And if we 

 wish to determine by calculation the depth at which that 



