Alfred Russel Wallace 



spend a holiday, with Henslow, in that locality, a holiday 

 which was, indeed, to form part of his famous voyage. 



By means of his explorations in the neighbourhood of 

 Cambridge, and one or two visits to North Wales, Dar- 

 win's experimental knowledge of geology and allied sciences 

 was considerably increased. In his zeal for collecting beetles 

 he employed a labourer to ^' scrape the moss off old trees in 

 winter, and place it in a bag, and likewise to collect the 

 rubbish at the bottom of the barges in which reeds were 

 brought from the fens, and thus . . . got some very rare 

 species.'' 



During the summer vacation of 1831, at the personal 

 request of Henslow, he accompanied Professor Sedgwick 

 on a geological tour in North Wales. In order, no doubt, 

 to give him some independent experience, Sedgwick sent 

 Darwin on a line parallel with his own, telling him to 

 bring back specimens of the rocks and to mark the stratifi- 

 cation on a map. In later years Darwin was amazed to 

 find how much both of them had failed to observe, *^yet 

 these phenomena were so conspicuous that ... a house 

 burnt down by fire could not tell its story more plainly 

 than did the valley of Cwm Idwal." 



This tour was the introduction to a momentous change 

 in his life. On returning to Shrewsbury he found a letter 

 awaiting him which contained the offer of a voyage in 

 H.M.S. Beagle. But oAving to several objections raised by 

 Dr. Darwin, he wrote and declined the offer ; and if it had 

 not been for the immediate intervention of his uncle, Mr. 

 Josiah Wedgwood (to whose house he went the following 

 day to begin the shooting season), who took quite a different 

 view of the proposition, the '^ Journal of Kesearches during 

 the Voyage of H.M.S. Beagle/^ by Charles Darwin, would 

 never have been written. 



At length, however, after much preparation and many 



18 



