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},” 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 
1L. L. 1. p. 276. 
