GEOLOGY IN SERVICE OF MAN WATTS 281 



strategic abilitj^ would reap as much advantage from a knowledge 

 of the underlying canons of topographic relief as the geologist 

 would from a study of the principles of military topography. It 

 was a wise scheme to train the British home and overseas armies 

 on ground similar in kind and in relief to that on which they were 

 about to fight in France; but it should have been realized that 

 physical causes and the resultant topographical relief differ in 

 essential particulars in temperate and tropical climates. 



INTELLECTUAL SERVICE 



Innumerable as are the services which ih' science of geology 

 has rendered to man on the material side, these are at least equalled, 

 if not outweighed, by those rendered on the intellectual side, either 

 in the direct application of its principles to the life of mankind, or 

 in the aid given to other sciences and the confidence engendered in 

 such of their conclusions as can be tested in the light of geological 

 history. 



Througliout most of its range and in its more special directions, 

 geology, like zoology and botany, is mainly an observational science. 

 Multitudes of facts have to be observed and grouped, and as much 

 skill is required in selecting from them the more significant and 

 decisive as in collecting them. Experiment for the most part is of 

 service in the criticism and verification of tentative theories; and, on 

 the physical and applied sides more especially, it is becoming of 

 great value. But the process of examination in chief, and the cross- 

 examination in the field by a highly qualified and fully trained 

 observer, are so exhaustive that not very much is L^ft to submit for 

 checking to the experimenter. 



Even more than either of these two sciences is geology an open- 

 air science and one which calls for and imparts a love of nature that 

 can not but deepen as knowledge increases. Its most interesting 

 work lies as a rule in the districts most attractive for other reasons. 

 In the course of geological work the country must be thoroughly 

 traversed, and, when possible, should be seen again and again, in 

 all lights, under all aspects, and at all times and seasons. 

 Hypotheses grow but slowly, and call for constant checking or 

 verification in the field, the gradually growing ideas being an in- 

 tensive spur in the collection of new facts or the reobservation of old 

 ones, and in the comparison with like or unlike cases published or 

 unpublished. But, as they grow, hypotheses give to their framer 

 a power of prediction, more precise as the hypothesis is better 

 founded ; and one of the most fascinating i)arts of his work is the 

 testing out of such predictions and the making of crucial observa- 



