326 HEROES OF SCIENCE. 



principles, and as evidence strengthening the sys- 

 tem necessarily arising out of the admission of such 

 principles, which as you know, are neither more nor 

 less than, that no causes whatever have, from the 

 earliest time to which we can look back to the 

 present, ever acted, but those 7iow acting ; and that 

 they never acted with different degrees of energy 

 from that which they now exert." If I can but 

 earn the wherewith to carry on the war, or rather, 

 its extraordiiiary costs, depend upon it I will waste 

 no time in book-making for lucre's sake." 



Lyell's long-expected book on the " Principles of 

 Geology" was published in 1830, and it made a 

 very considerable sensation, and was warmly com- 

 bated and abused. Now it is admitted as the most 

 conclusive and useful of introductory books, fit 

 for a youth, and eminently good in its tone. Then 

 the man, ever on the move, left for the Pyrenees, 

 and studied the formations there, and especially 

 devoted himself to the explanation of ripple-marks 

 in the hundreds of feet of rock, and noticed the 

 effects of water-borne and air-carried sand in 

 accumulating flats of ripples one over the other. 

 In 1 83 1 Lyell accepted the position of Professor of 

 Geology in King's College, London, and he gave 

 courses of lectures there in 1832 and 1833 > ^^^d he 

 became engaged to Mary, the eldest daughter of 

 Mr. Leonard Horner, a geologist of considerable 

 reputation, and a thoroughly liberal-minded man. 

 Mr. Horner was a great friend of Lyell's before the 

 engagement; and was a most painstaking man and 



