Temperature of the Terrestrial Globe. 15 



by the difference of specific gravity, produced by the difference of 

 temperature of the superposed strata. The experiments of Count 

 Rurnford induced this excellent experimenter to conclude that all 

 fluids are perfect non-conductors of heat. Mine have proved that 

 air and water transmit heat, but with extreme slowness, analogous to 

 that with which chemical substances spontaneously mingle with each 

 other, by their physical attractions. This principle of cooling must 

 then be considered as of very small efficiency, even when the tem- 

 perature of the warm medium is continually renewed ; and the nu- 

 merical law of heat at different distances from the surface of this me- 

 dium, would become near this surface a very divergent progression, 

 whose difference at some distances would amount to nothing. Now 

 maritime experiments present a series absolutely opposed to this* 

 This element of the diminution of temperature, therefore does not 

 explain the phenomenon of the diminution observed in the contrary 

 direction. 



This marine phenomenon, must then, according to the hypothesis, 

 be attributed to the second principle of refrigeration, and Mr. Four- 

 ier admits it as such, attributing to it even the vast and rapid currents 

 which pervade the whole mass of ocean. But these currents are 

 observed only at the surface of deep seas, and not at great depths. 

 The experiments of M. Lenz indicate no current from the depth of 

 a few hundred to one thousand fathoms. His colossal pendulum, it 

 is true did not always maintain a perpendicular direction. But as 

 M. Lenz had only a few hours of calm, the surface of the sea had 

 not yet come to a state of perfect repose, and the vessel moved 

 more or less rapidly in the direction of the waves. Thus the chord 

 of his bathometer was rarely found in a vertical position ; but as this 

 angle was always found in a plane with the vessel's line of progress, 

 and as the mean of all these observations (very much diversified by 

 her rolling and pitching,) was only 9 degrees, there is no reason for 

 admitting that these angles with the vertical were the product of cur- 

 rents in the interior of the sea. 



In theory we must admit that at the bottom of the Ocean the up- 

 per surface of the earth, and the inferior surface of the envelope of 

 Water with which it is covered are of the same temperature, that the 

 temperature of the earth (in the hypothesis which we are examining), 

 goes on increasing towards the interior and as this has been the case 

 for ages, or thousands of ages, the temperature of these contiguous 

 surfaces, as well as that of dry continents, may be regarded as ab- 



