discover the hUernal Constltutum of our Earth, SI 



Hence it may be computed, that if the same law of conden- 

 ^sation continued, Air would become as dense as Water at the 

 depth of 33^ miles; it would even acquire the density of quick- 

 silver at a farther depth of 163 ^ miles. 



The idea which I formerly threw out in the article Meteoro- 

 logy, of the Supplement to the Encyclopaedia Britannica, that 

 the ocean may rest on a subaqueous bed of compressed air, is 

 therefore not devoid of probability. Supposing the rate of con- 

 traction were to proceed more slowly than at first, still the re- 

 quired measure of condensation would be attained at a depth 

 which forms a very small part of the radius of the globe. 



But Water, under the weight of an enormous column, must 

 likewise largely contract. At the depth of 93 miles, it would 

 be compressed into half its former bulk; and. at the depth of 

 S62^ miles, it would acquire the ordinary density of quicksilver. 

 Even marble itself, subjected to its own pressure, would become 

 twice as dense as before, at the enormous depth of 287| miles. 



It is curious to remark, that, from its rapid compressibility, 

 air would sooner acquire the same density with water, than this 

 fluid would reach the condensation of marble. For the coinci- 

 dence of Air and Water, ihejbrmula becomes 



^« = 15649936—^^1^^=1^122? Log. 840; whence the 



depth is 35 J miles. 



For equal densities of water and marble, the Jbrmula is 



2 ^f,aA(^f^aa 7287200.2415707 ,- ^ ,. , , ,, , ,, 



w^ = 15649936 4871 4Q^ ^^* ' ^ depth 



descends to 172/^ miles. 



If we calculate for a depth of 395 f miles, which is only the 

 tenth part of the radius of the earth, we shall find that Air 

 would attain the enormous density of 101960 billions ; while, at 

 the same depth. Water would acquire but a density of 4.349^ 

 and IVtarble only 3.8095. 



At the centre of the earth, the several formuke will become 

 simpler. The logarithm of the final augmented density would 



, . . . 15649936 . „, , 15649936 , „ ^.^ ,, 

 be for Air q,qq^ ? for Water ? and for Marble 



15649936 



7287200" "^ would hence reach the inconceivable density 



