HISTORY OF GEOLOGY AND PALEONTOLOGY. 



different parts of the Continent. In 1831 he gave a course of 

 lectures on geology in King's College in London. But Lyell 

 would not undertake the duties of a Professor for any length 

 of time. He resigned his post in order to devote himself 

 exclusively to science. His wife Mary, a daughter of the 

 geologist Leonard Horner, proved a devoted companion in 

 all his journeys throughout their long, happy, childless mar- 

 riage, and was a zealous helper to him in his work, sparing 

 him many of the laborious researches that might have been 

 arduous for his weak eyes. 



The publication of the Principles placed Lyell in the first 

 rank of geologists, and won for him universal recognition as a 

 fine observer, an acute thinker, and a master of language. The 

 success of his work was unexampled. In spite of its compre- 

 hensive character, six editions of it appeared between 1830 and 

 1840, a seventh in the year 1847, the eighth in 1850, the ninth 

 in 1853, the tenth in 1866, the eleventh in 1872, and the 

 twelfth shortly after his death in 1875. Throughout the long 

 space of thirty-five years between the first and last editions, 

 Lyell was indefatigable in his efforts to improve the work, to 

 widen his range of knowledge by his annual tours, and to test 

 his opinions by intercourse with his geological colleagues. 

 Lyell was as much at home in the geology of Germany, 

 Belgium, France, Switzerland, and Italy as in that of Great 

 Britain. 



In the summer of 1834 he visited Denmark and Sweden, in 

 i837 1 Norway, and in 1841 he undertook his first journey to 

 North America. He stayed there one year, on this occasion 

 visiting chiefly Canada and the eastern part of the United 

 States. He published an account of the journey in 1845, in a 

 special work entitled Travels in North America. Soon after 

 the publication of this volume, Lyell again crossed to America 

 and investigated the southern states. The account of this 

 journey appeared in another independent volume in 1849, and 

 the work contained, in addition to geological observations, 

 much interesting matter regarding the people and their social, 

 political, and religious relations. 



In 1854, accompanied by the German geologist Hartung, 

 Lyell spent several weeks in Madeira and the Canary Isles, 

 where he studied the volcanoes. In his later years he re- 

 visited North America twice, and went to Sicily and other 

 parts of Europe, sometimes for the investigation of some 



