366 Darwin and Geology 



At the end of 1836 Darwin had settled himself in lodgings in 

 Fitzwilliam Street, Cambridge, and devoted three months to the 

 work of unpacking his specimens and studying his collection of rocks. 

 The pencilled notes on the Manuscript Catalogue in the Sedgwick 

 Museum enable us to realise his mode of work, and the diligence 

 with which it was carried on. The letters M and H, indicate the 

 assistance he received from time to time from Professor Miller, 

 the crystallographer, and from his friend Henslow. Miller not 

 only measured many of the crystals submitted to him, but 

 evidently taught Darwin to use the reflecting goniometer himself 

 with considerable success. The "book of measurements" in which 

 the records were kept, appears to have been lost, but the pencilled 

 notes in the catalogue show how thoroughly the work was done. 

 The letter R attached to some of the numbers in the catalogue 

 evidently refers to the fact that they were submitted to Mr Trenham 

 Reeks (who analysed some of his specimens) at the Geological Survey 

 quarters in Craig's Court. This was at a later date when Darwin was 

 writing the Volcanic Islands and South America. 



It was about the month of March, 1837, that Darwin completed 

 this work upon his rocks, and also the unpacking and distribution 

 of his fossil bones and other specimens. We have seen that November, 

 1832, must certainly be regarded as the date when he first realised 

 the important fact that the fossil mammals of the Pampean formation 

 were all closely related to the existing forms in South America ; 

 while October, 1835, was, as undoubtedly, the date when the study of 

 the birds and other forms of life in the several islands of the Galapagos 

 Islands gave him his second impulse towards abandoning the prevalent 

 view of the immutability of species. When then in his pocket-book 

 for 1837 Darwin wrote the often quoted passage : " In July opened 

 first note-book on Transmutation of Species. Had been greatly 

 struck from about the month of previous March on character of 

 South American fossils, and species on Galapagos Archipelago. 

 These facts (especially latter), origin of all my views 1 /' it is clear 

 that he must refer, not to his first inception of the idea of evolution, 

 but to the flood of recollections, the reawakening of his interest in 

 the subject, which could not fail to result from the sight of his 

 specimens and the reference to his notes. 



Except during the summer vacation, when he was visiting his 

 father and uncle, and with the latter making his first observations 

 upon the work of earthworms, Darwin was busy with his arrange- 

 ments for the publication of the five volumes of the Zoology of the 

 Beagle and in getting the necessary financial aid from the govern- 

 ment for the preparation of the plates. He was at the same time 



1 L. L. i. p. 276. 



