al the Surface of the Earth. 181 



iiot increase, hut are so adjusted, that when they reach certain 

 limits they recede, and within tliis state of oscillation the stabi- 

 lity of the entire system is for ever secured. It would gratify 

 tile mind, could it i)e shown that a similar system exists with 

 regard to the subordinate parts ; or, if not, that a state of per- 

 manence in these parts will be ultimately established, compati- 

 ble with the operation of that more general law under which the 

 order of the universe is maintained. In the structure of the 

 plobe, however, and in the operations to which it is subject, 

 there are evident causes of disintegration, which seem incom- 

 patible with a state of permanence, and from which, in the pro- 

 gress of time, those arrangements which constitute it a habitable 

 world must apparently be subverted. For tlie Huttonian theory 

 has been claimed tiie praise (with v/hat justice need not here 

 be inquired) of unfolding a system of renovation corresponding 

 to this waste. In the opposite theory, no similar attempt has 

 been made ; its object has i)een merely to trace the arrangements 

 which exist in the mineral kingdom, and from these to infer the 

 order and mode in which they have been framed ; nor have any 

 causes been jiointed out, as, "indeed, none seem to follow from 

 the princij)les of tiie theory, by which that disintegration, the 

 occurrence of which in past periods is so clearly marked, and the 

 operation of which, even at present, is to be traced, may be re- 

 paired. 



If the view, however, which has been given of the relation of 

 the temperature of the earth to solar heat be just, this deficiency 

 may perhaps be su})plied. Inequality of temperature is the great 

 source of cliange and of disintegration at the surface ; the ex- 

 pansion and contraction from alternations of heat and cold, the 

 absorption and expulsion of humidity from the same causes, the 

 <hstending force of congelation, and" the rapid precipitation and 

 :low of water, which are the principal, or rather the sole, disin- 

 tegrating processes of general or uniform operation, being the 

 1 ijults of it. When inequality of temperature, therefore, shall 

 cease, or be restrained v.-ithin much narrower limits, an order 

 mav be established of less vicissitude, and less waste, than that 

 which now prevails, and tlie stability of which may even remaiq 

 unimpaired for indefiiiite time. 



This view, if it is not carrying the speculation too far, may 

 even be extended to all the parts of our solar system, and the 

 condition of eacli planet -may be connected in permanence wirli 

 tliat law which appears to regulate the constitution of the uni- 

 verse. Considering this earth as passing through a series of re- 

 volutions from its chaotic state to a more permanent and perfect 

 torm, the different planets may be regarded as in a similar pro- 

 gression. A<;:ronomer3 have often traced the cnalory which ex- 



M 3 i,rs 



