330 



EECEEATIVE SCIENCE. 



power, the abode of forces whicb. only liint of 

 their being by the exhibition of marked phe- 

 nomena on the surface. 



" ^Vhen the Cyclops o'er their anvils sweat, 

 And their swoln sinews echoing blows repeat, 

 From the volcano gross eruptions rise, 

 And curling sheets of smoke obscure the skies." 



Yet a thickness of 100 miles in the crust con- 

 veys bixt little idea of strength to resist pres- 

 sure from without and within. To a globe of 

 8000 miles diameter, such a crust will be pro- 

 portionately much thinner than the rind of 

 an orange, and hence but a delicate beam 

 between the opposing forces fighting for a 

 balance. Its thinness, indeed, renders easy of 

 explanation the phenomenon of earthquakes, 

 for all below being in a state of commotion and 

 ebullition, any change upon the surface of the 

 earth, acting on a crust so thin and hollow, 

 would cause rents and fissures, through which 

 the fire would burst and rage upon the sur- 

 face until the falling masses closed the chasm 

 again. What agent is there to produce such 

 1 change upon the surface? What agent of 

 sufficient force to splinter a roofing of 100 

 miles' thickness ? This soft, invisible, yield- 

 ing, and embracing atmosphere, fanning the 

 cheek with coolness, kissing the spring daisy 

 as it dances over emerald meadows, or tearing 

 up forests by the roots and hurling their tim- 

 bers to the skies ! This atmosphere is the 

 essential agent, powerful for all pxirposes of 

 disturbance, and ever ready to bring its 

 power into operation. On every square inch 

 of the earth's surface the atmosphere presses 

 with a weight of 15 pounds. On every square 

 foot the pressure amounts to 2160 pounds, or 

 one ton nearly. Over the whole earth, there- 

 fore, the pressure of the atmosphere is equal 

 to 12,043,468,800,000,000,000 pounds. Sup- 

 pose the barometer to fall two inches over 

 100 miles of country, that fall represents the 

 removal of 1,858,560,000 tons of pressure. 

 The expansion from within continuing the 

 same, will not the equilibrium between the 

 heat within and tlie air without be at once 



destroyed P Can we wonder that Typha;us, 

 panting and struggling with the weight of 

 hills and plains upon his heart, will stir himself 

 afresh as the weight of his burthen lessens ? — 

 that, indeed, the internally heated materials, 

 no longer held down by the full pressure of the 

 atmosphere, will heave up the crust, and cause 

 crackings of the surface and earthquake com- 

 motions ? that in the explosion cities will 

 fall, hills be swallowed up, and plains elevated P 

 that sheets of steam, escaping from the newly 

 opened vents, will roll over the undulating 

 surface P that convulsions of all kinds will 

 occur, until, by the return of things to a 

 balance, tranquillity is restored P One simple 

 general fact corroborates this hypothetical 

 view of the production of an earthquake, and 

 it is this — that &fall of the barometer invari- 

 ably precedes the convulsions of an earth- 

 quake. 



Many inquirers, who have seen the neces- 

 sity of admitting the theory of Internal Heat, 

 have, after conviction, suffered many pangs 

 in the contemplation of the possible conse- 

 quences of the theory. If the earth is stea- 

 dily parting with heat, will it not at last cool 

 down into a lifeless frozen crystal, the abode 

 no longer of life and beauty, but of death in 

 his most hideous form P Let us never fear 

 consequences, but repose faith in the perfec- 

 tion of the entire scheme as an evidence of 

 the constant protection of an universal Father. 

 The early astronomers feared consequences, 

 and built up their theory of the destruction 

 of aU things under the necessities of pertur- 

 bation ; but in the progress of mathematical 

 astronomy it has been shown that perturba- 

 tions are compensatory, and have no influence 

 on the term of existence allotted to the bodies 

 experiencing them. How fast, then, does our 

 earth cool ^ how rapidly does it approach to 

 the supposed state of a lifeless crystal P 



If the earth, in its present condition, were 

 projected into a medium having a tempera- 

 ture of 58' below zero of Fahrenheit, it 

 would not cool more in 2,000,000 years than 



