288 THE EVOLUTION OF PETROLOGICAL IDEAS. 



That it was necessary to put a curl) on the unbridled license of 

 geological speculation, and to emphasize the importance of diligence 

 and accuracy in the observation of facts, will be admitted by all students 

 of the history of our science; but it is well to remember that there is 

 a scientific, as well as an unscientific, use of the imagination. The chief 

 glory of science is, not that it ])roduces an amelioration of the condi- 

 tions under which we live, but that it continually enlarges our view, 

 introduces new ideas, new ways of looking at things, and thus con- 

 tributes in no small degree to the intellectual development of the 

 human race. 



■ It is now generally recognized that the state of advancement of a 

 science must he measured, not by the number of facts collected, but liy 

 the niunber of facts coordinated. The old Baconian idea that it was 

 only necessary to collect facts and pigeonhole them according to rule, 

 in order to make the most brilliant discoveries, has been somewhat 

 discredited b}" the history of scientific progress. Speaking on this 

 subject, De Morgan saj^s: 



"Modern discoveries have not been made b}^ large collections of 

 facts, with subsequent discussion, separation, and resulting deduction 

 of a truth thus rendered perceptible. A few facts have suggested an 

 hypothesis which means a supposition proper to explain them, the 

 necessary results of this supposftion are worked out, and then, and not 

 till then, other facts are examined, to see if these ulterior results are 

 found in Nature. * * * What are large collections of facts for? 

 To make theories from, says Bacon; to tr}^ ready-made theories by, 

 says the history of discovery; it's all the same, says the idolater; non- 

 sense, say we." 



Hutton appears to have been of De Morgan's way of thinking. He 

 pondered over the facts that he had observed in England, France, and 

 Scotland, and formulated his theory of the earth. He then went again 

 into the field to test the consecjuences of his theor}^, and verified them. 

 He never seems to have thought it worth while to describe isolated 

 facts, or the structure of particular districts, except in so far as they 

 illustrated his theory, although no one was l)etter qualified to do this, 

 as all readers of his description of the unconformity at Siccar Point, 

 of the granite veins in Glen Tilt, or of the geological features of 

 Arran will readily admit. His joy at the discovery of the granite 

 veins in (xlen Tilt can l)e easily understood. His theory required that 

 they should exist, and they were found, not by chance, but because 

 they were looked foi'. And we may ))e sure that the joy did not arise 

 from gratified vanity, for, as Phiyfair says. h(> was one of thos(^ who 

 took more delight in the coiitemi)lation of trutii than in the praise of 

 having disc(>\-ered it. 



In thus calling attention to the inipoi-tance of ideas in scientific 

 research, 1 trust it will not })c thought that 1 am advocating a return 

 to the condition of things which prevailed in the early days of geolog- 



