438 



SIR CHARLES LYELL 



duced the former revolutions of the globe, and those now in 

 cvery-day operation. It appeared clear that the earlier geol- 

 ogists had not only a scanty acquaintance with existing 

 changes, but were singularly unconscious of the amount of 

 their ignorance. With the presumption naturally inspired by 

 this unconsciousness, they had no hesitation in deciding at 

 once that time could never enable the existing powers of 

 nature to work out changes of great magnitude, still less 

 such important revolutions as those which are brought to 

 light by .Geology. They therefore felt themselves at liberty 

 to indulge their imaginations in guessing at what might 

 be, rather than enquiring what is; in other words, they 

 employed themselves in conjecturing what might have been 

 the course of Nature at a remote period, rather than in 

 the investigation of what was the course of Nature in their 

 own times. 



It appeared to them far more philosophical to speculate 

 on the possibilities of the past, than patiently to explore the 

 realities of the present ; and having invented theories under 

 the influence of such maxims, they were consistently unwil- 

 ling to test their validity by the criterion of their accordance 

 with the ordinary operations of Nature. On the contrary, 

 the claims of each new hypothesis to credibility appeared 

 enhanced by the great contrast, in kind or intensity, of the 

 causes referred to and those now in operation. 



Never was there a dogma more calculated to foster indo- 

 lence, and to blunt the keen edge of curiosity, than this 

 assumption of the discordance between the ancient and exist- 

 ing causes of change. It produced ~. state of mind unfavour- 

 able in the highest degree to the candid reception of the 

 evidence of those minute but incessant alterations which 

 every part of the earth's surface is undergoing, and by which 

 the condition of its living inhabitants is continually made to 

 vary. The student, instead of being encouraged with the 

 hope of interpreting the enigmas presented to him in the 

 earth's structure instead of being prompted to undertake 

 laborious enquiries into the natural history of the organic 

 world, and the complicated effects of the igneous and aqueous 

 causes now in operation was taught to despond from the 

 first. Geology, it was affirmed, could never rise to the rank 



