THE LAWS OF GEOLOGICAL ACTION. 9 



volcanoes, must have been far more intensely active than we 

 can conceive of from anything that we can see at the present 

 day. By the same hypothesis, the sun is a cooling body, and 

 must have at one time possessed a much higher temperature 

 than it has at present. But increased heat of the sun would 

 seriously alter the existing conditions affecting the evaporation 

 and precipitation of moisture on our earth ; and hence the 

 aqueous forces may also have acted at one time more power- 

 fully than they do now. The fundamental principle of catas- 

 trophism is, therefore, not wholly vicious; and we have reason 

 to think that there must have been periods very remote, it is 

 true, and perhaps unrecorded in the history of the earth in 

 which the known physical forces may have acted with an inten- 

 sity much greater than direct observation would lead us to 

 imagine. And this may be believed, altogether irrespective of 

 those great secular changes by which hot or cold epochs are 

 produced, and which can hardly be called " catastrophistic," as 

 they are produced gradually, and are liable to recur at definite 

 intervals. 



Admitting, then, that there is a truth at the bottom of the 

 once current doctrines of catastrophism, still it remains certain 

 that the history of the earth has been one of law in all past time, 

 as it is now. Nor need we shrink back affrighted at the vast- 

 ness of the conception the vaster for its very vagueness that 

 we are thus compelled to form as to the duration of geological 

 time. As we grope our way backward through the dark laby- 

 rinth of the ages, epoch succeeds to epoch, and period to period, 

 each looming more gigantic in -its outlines and more shadowy 

 in its features, as it rises, dimly revealed, from the mist and 

 vapor of an older and ever-older past. It is useless to add 

 century to century or millennium to millennium. When we pass 

 a certain boundary-line, which, after all, is i cached very soon, 

 figures cease to convey to our finite faculties any real notion of 

 the periods Avith which we have to deal. The astronomer can 

 employ material illustrations to give form and substance to our 

 conceptions of celestial space ; but such a resource is unavail- 

 able to the geologist. The few thousand years of which we have 

 historical evidence sink into absolute insignificance besides the 

 unnnumbered aeons which unroll themselves one by one as we 

 penetrate the dim recesses of the past, and decipher with feeble 

 vision the ponderous volumes in which the record of the earth 

 is written. Vainly does the strained intellect seek to overtake 

 an ever-receding commencement, and toil to gain some adequate 



