Disturbance of the Crust of the Earth. 5 



accession of greatly heated matter would probably, if it did 

 not increase the heat of the crust, contribute to keep it up. 

 And as it appears that hot matter had invaded the crust at 

 many different epochs, before it was elevated into its present 

 shape, it seems reasonable to suppose that the temperature of 

 climate, in so far as the influence of that of the earth extend- 

 ed, was considerable.* 



It may be said that, according to these views, the crust of 

 the earth should have been acquiring heat from the interior, 

 since the period of the last cataclysm ; but that we have no 

 proof of this in the improvement of climate, but rather of 

 the contrary. The only proof we can have, is the result of a 

 long continued series of observations recently begun, at various 

 depths, in mines. For it is obvious there are causes inde- 

 pendent of the actual heat of the crust, which operate in the 

 regulation of climate. The causes of change in atmospheric 

 temperature are as yet obscure ; and although we see cer- 

 tain effects following certain apparent causes, such as boiste- 

 rous and wet weather coming after the appearance of the 

 aurora borealis, we are yet ignorant of the mode of connec- 

 tion between the phenomenon of the aurora and terrestrial 

 influences. It appears, however, probable, that climate de- 

 pends more on operations going on in the atmosphere than 

 on the actual heat of the crust ; and that if these were ab- 

 sent, and the heat of the crust and the sun's rays were left to 

 exercise their influence alone, our climate would be much 

 warmer than it is. Hence I should not think it fair to infer, 

 that because climate is deteriorated, the crust of the earth is 

 not returning to its normal state, and becoming warmer. 

 That change does take place in atmospheric conditions, ap- 

 pears to be unquestioned ; but, as yet, no observations have 

 been made, such as to ascertain the causes of such changes. 

 Electricity has much to do, no doubt ; but still, however nume- 

 rous and remarkable the discoveries of its modes of operating 



* When we consider tlio phenomenon of earthquakes, it seems likely 

 that some process is going on, such as a partial tearing of the strata, and 

 the filling up of rents ; and should another cataclysm take place, such as 

 again to break up the crust, it is probable that a fresh system of veins and 

 dykes will be exposed to view. 



