56 THE COMING [OH. 



But this plan appears to have been soon aban- 

 doned; and by the end of the year 1827, when he 

 had reached the age of thirty, Lyell had sent to the 

 printer the first manuscript of the Principles of 

 Geology, proposing that it should appear in the 

 course of the following year in two octavo volumes 43 . 



A great and sudden interruption to this plan 

 occurred however, for just at this time Lyell was 

 engaged in writing his review for the Quarterly of 

 Scrope's work on The Geology of Central France, and 

 while doing this his interest was so strongly aroused 

 by the accounts of the phenomena exhibited in the 

 Auvergne, that he was led for a time to abandon the 

 task of seeing his own book through the press ; and, 

 having induced Murchison and his wife to accompany 

 him, set off on a visit to that wonderful district. He 

 also felt that, before completing the second part of his 

 book, he needed more information concerning the 

 Tertiary formations, especially in Italy. 



Lyell had been very early convinced of the 

 supreme importance of travel to the geologist. In 

 a letter to his friend Murchison he said : ' We must 

 preach up travelling, as Demosthenes did " delivery " 

 as the first, second and third requisites for a modern 

 geologist, in the present adolescent state of the 



science 44 .' 



And Professor Bonney has estimated that so far 

 did he himself practise what he preached, that no 



