i845] LYELL'S ' PRINCIPLES.' 309 



Sometimes in the beginning of a chapter, in one paragraph 

 your course was traced through a half dozen places ; anyone, 

 as ignorant as myself, if he could be found, would prefer such 

 a disturbing paragraph left out. I cut your map loose, and I 

 found that a great comfort ; I could not follow your engraved 

 track. I think in a second edition, interspaces here and there 

 of one line open, would be an improvement. By the way, I 

 take credit to myself in giving my Journal a less scientific air 

 in having printed all names of species and genera in Romans ; 

 the printing looks, also, better. All the illustrations strike 

 me as capital, and the map is an admirable volume in itself. 

 If your ' Principles ' had not met with such universal admi- 

 ration, I should have feared there would have been too much 

 geology in this for the general reader ; certainly all that the 

 most clear and light style could do, has been done. To my- 

 self the geology was an excellent, well-condensed, well-di- 

 gested resume of all that has been made out in North Amer- 

 ica, and every geologist ought to be grateful to you. The 

 summing up of the Niagara chapter appeared to me the 

 grandest part ; I was also deeply interested by your discussion 

 on the origin of the Silurian formations. I have made scores 

 of scores marking passages hereafter useful to me. 



All the coal theory appeared to me very good ; but it is 

 no use going on enumerating in this manner. I wish there 

 had been more Natural History ; I liked all the scattered 

 fragments. I have now given you an exact transcript of my 

 thoughts, but they are hardly worth your reading. . . . 



C. Darwin to C. Lyell. 



Down, August 25th [1845]. 



My dear Lyell, — This is literally the first day on which 

 I have had any time to spare ; and I will amuse myself by 

 beginning a letter to you. . . . 



I was delighted with your letter in which you touch on 

 Slavery ; I wish the same feelings had been apparent in your 

 published discussion. But I will not write on this subject, I 



