xii 



G-eology in King's College, London — an appointment, however, which he 

 did not long retain. His summers were devoted to excursions through 

 different parts of the British Islands and to tours on the continent, not 

 so much with the view of doing original field-work himself as to see 

 with his own eyes the ground and the rocks described by others, and thus 

 to be better enabled to realize their descriptions and to judge of the rela- 

 tive importance of their contributions to geology. In this way he tra- 

 versed Europe, from the mountains of Scandinavia to the shores of Sicily, 

 and extended his travels into the Canary Islands. Anxious still further 

 to enlarge his experience, he went to the rTnited States and spent some 

 time in a geological tour there, of which the results were published in 

 1841 in his volumes of a ' Visit to the United States.' A few years later 

 he again crossed the Atlantic and collected materials, which appeared 

 in 1815 in his ' Second Yisit to the United States,' as well as in nume- 

 rous papers published in various scientific journals. 



Though he wrote many minor papers and a few large memoirs on 

 original researches of his own, most of his work appeared from time to 

 time in the successive editions of his ' Principles ' and ' Elements.' 

 Among his most important memoirs should be mentioned his paper on the 

 Consolidation of Lava on steep slopes upon Etna, published in the ' Philo- 

 sophical Transactions ' for 1858. This paper may be regarded as having 

 finally exploded the elevation-crater theory of Von Buch, although the 

 admirable memoirs of Scrope had already given that theory its death- 

 blow. 



Perhaps the best idea of the solid services rendered by Lyell to geology 

 is obtained by looking back at the condition of the science when he first 

 began to study it, and by contrasting that state vdth the luminous exposition 

 of the subject in the early editions of his 'Principles.' To m^en who had 

 been compelled to gain their general view of geology from such works as 

 Daubuis son's ' Traite ' or Cuvier's ' Theory of the Earth,' the appearance 

 of Lyell's volumes must have been of the nature of a new revelation. 

 Erom vague statements about early convulsions and a higher intensity of 

 all terrestrial energy culminating in periodic catastrophes, they were led 

 back, with rare sagacity and eloquence, to the living, moving world around 

 them, and taught to find there, in actual progress now, the analogues of 

 all that they could discover to have been effected in the geological past. 



The keynote which Lyell struck at the very outset was, that in geology 

 the past can be understood only through the present, that the forces now 

 in operation are quite powerful enough to produce changes as stupendous 

 as any which have taken place in former times, provided only that they 

 get time enough for their task. 



These views were not promulgated for the first time by the author of 

 the ' Principles of Geology.' In cruder form they had been earnestly urged 

 by Hutton, and eloquently illustrated and extended by Playfair ; but after 

 much turmoil and conflict of opinion, they had very generally been allowed 



