3'^ Ampere's Theory of the Fortnation of the Globe, 



not only towards the exterior of the globe, but likewise towards 

 its interior. 



In proportion, therefore, as the oxidation of the crust advan- 

 ces, the seat of the chemical actions, and consequently \\\t focus 

 of the subterranean heat, will approach nearer and nearer to the 

 centre. 



What has been just remarked, says M. Ampere, may seem at 

 first sight at variance with certain observed facts. It has been 

 noticed, that from the surface down to a certain depth the earth's 

 temperature is progressive, and we are hence disposed to con- 

 clude, that this same increase continues even to the centre, or at 

 least down to the point at which the contents would exist in a 

 state of fusion. 



The observations themselves are good, but the conclusion 

 drawn from them may well admit of objection. 



Let us, in the first place, suggest, that this increase of tem- 

 perature from the surface to a certain depth furnishes no ground 

 for setting aside our hypothesis, inasmuch as, even upon our own 

 assumption, it is a necessary consequence, seeing that the most 

 intense heat ought to exist at the line of contact between the 

 metallic nucleus of the oxidized bed above it, and consequently 

 far below the greatest depth that has ever been reached by man. 



Let us add, that man has as yet sunk scarcely a league into 

 the interior of the earth, so that he is acquainted by actual ob- 

 servation only with what takes place over y^^ooth part of the 

 diameter of the globe. To infer from what has been remarked in 

 this small portion of the diameter, the nature of what is taking 

 place throughout the whole extent of the globe, seems very pre- 

 cipitate, for it is an established rule in physics, that we have no 

 right to regard a fact observed as indicating a general law, until 

 it has been found to hold good with respect to the larger portion 

 of the scale over which it is extended. 



Those who maintain, that the internal nucleus of the globe is 

 in a liquid state, do not appear to have reflected upon the action 

 which the moon would f^xercise on this enormous fluid mass ; an 

 action, from which would result tides analogous to those of our 

 seas, but infinitely more terrible in their effects, both on account 

 of the extent and the density of the liquid. It is difficult to con- 

 ceive, how the casing of the earth could offer resistance to the 



