2 The Founders of Geology LECT. 



contact with strenuous, patient, and noble natures never 

 fails to reveal. Moreover, it has a double value in its 

 bearing on our own progress in scientific work. A retro- 

 spect of this kind leads to a clearer realization of the 

 precise position at which we have arrived, and a wider 

 conception of the extent and limits of the domain of 

 knowledge which has been acquired. On the other hand, 

 by enabling us to comprehend how, foot by foot, the 

 realms of science have been painfully conquered, it 

 furnishes suggestive lessons as to tracks that should be 

 avoided, and fields that may be hopefully entered. 



In no department of natural knowledge is the adoption 

 of this historical method more necessary and useful than it 

 is in Geology. The subjects with which that branch of 

 science deals are, for the most part, not susceptible of 

 mathematical treatment. The conclusions formed in 

 regard to them, being often necessarily incapable of rigid 

 demonstration, must rest on a balance of probabilities. 

 There is thus room for some difference of opinion both 

 as to facts and the interpretation of them. Deductions 

 and inferences which are generally accepted in one age 

 may be rejected in the next. This element of uncertainty 

 has tended to encourage speculation. Moreover, the 

 subjects of investigation are themselves often calculated 

 powerfully to excite the imagination. The story of this 

 earth since it became a habitable globe, the evolution of 

 its continents, the birth and degradation of its mountains, 

 the marvellous procession of plants and animals which, 

 since the beginning of time, has passed over its surface, 

 these and a thousand cognate themes with which geology 

 deals, have attracted numbers of readers and workers to its 



