vm 



owed to one whom he calls (in one of his letters) his " dear old 

 master in Natural History." (II, p. 217.) It was by Henslow's 

 advice that Darwin was led to break the vow he had registered 

 against making an acquaintance with geology; and it was through 

 Henslow's good offices with Sedgwick that he obtained the oppor- 

 tunity of accompanying the Geological Professor on one of his 

 excursions in Wales. He then received a certain amount of practical 

 instruction in Geology, the value of which he subsequently warmly 

 acknowledged. (I, p. 237.) In another direction, Henslow did him 

 an immense, though not altogether intentional service, by recom- 

 mending him to buy and study the recently published first volume of 

 Lyell's ' Principles.' As an orthodox geologist of the then dominant 

 catastrophic school, Henslow accompanied his recommendation with 

 the admonition on no account to adopt Lyell's general views. Bat the 

 warning fell on deaf ears, and it is hardly too much to say that 

 Darwin's greatest work is the outcome of the unflinching application 

 to Biology of the leading idea and the method applied in the ' Prin- 

 ciples ' to Geology.* Finally, it was through Henslow, and at his 

 suggestion, that Darwin was offered the appointment to the " Beagle " 

 as naturalist. 



Duiing the latter part of Darwin's residence at Cambridge the 

 prospect of entering the Church, though the plan was never formally 

 renounced, seems to have grown very shadowy. Humboldt's 

 ' Personal Narrative,' and Herschel's ' Introduction to the Study 

 of Natural Philosophy,' fell in his way and revealed to him his real 

 vocation. The impression made by the former work was very strong. 

 "My whole course of life," says Darwin in sending a message to 

 Humboldt, "is due to having read and re-read, as a youth, his 

 personal narrative." (I, p. 336.) The description of Teneriffe 

 inspired Darwin with such a strong desire to visit the island, that 

 he took some steps towards going there — inquiring about ships, and 

 so on. 



But, while this project was fermenting, Henslow, who had been 

 asked to recommend a naturalist for Captain Fitzroy's projected ex- 

 pedition, at once thought of his pupil. In his letter of the 24th August, 

 1831, he says : " I have stated that I consider you to be the best 

 qualified person I know of who is likely to undertake such a situation. 

 I state this — not on the supposition of your being a finished naturalist, 

 but as amply qualified for collecting, observing, and noting anything 

 worthy to be noted in Natural History .... The voyage is to 



* " After my return to England it appeared to me that by following the example 

 of I/yell in Geology, and by collecting all facts which bore in any way on the varia- 

 tion of animals and plants under domestication and nature, some light might perhaps 

 be thrown on the whole subject [of the origin of species]." (I, p. 83.) See also 

 the dedication of the second edition of the ' Journal of a Naturalist.' 



