196 THIRTEENTH LETTER ON GLACIERS. [1840. 



This motion harmonises sufficiently well with the numbers 

 found in page 193, if we allow for the acceleration manifestly 

 due to the rapid declivity which commences immediately below 

 station W. 



This interesting discovery forms a curious pendant to the 

 history of De Saussure's ladder, believed to have been found 

 in fragments opposite Trelaporte, as fully detailed in my Travels, 

 page 86 ; but this new case is much better ascertained in all 

 its particulars. 



I may here mention, as the subject suggests it, another 

 proof of the extraordinarily conservative power of the ice even 

 upon the most seemingly destructible bodies. On the 20th July 

 1846, 1 found on the surface of the ice at station Q (opposite the 

 Glacier of Charmoz), all within a few feet of each other, four of the 

 small wooden pins which I had left there in making the expe- 

 riments in August 1844, described in my Eighth Letter, a 

 quantity of the thin string, and pieces of the birch broom then 

 used, and even a quantity of the loose straw which I used to 

 wrap round my shoes in cold weather. These were neither 

 decomposed nor blown away by the winds, nor had they fallen 

 into any of the numerous crevasses, but were lying on the sur- 

 face of the glacier (a very different surface, of course from that 

 on which they had really been left), as if they had been in use 

 at most but a few weeks before.* 



Glacier du Nant Blanc. This is a small glacier descending 

 from the foot of the Aiguille de Dru, exactly opposite the 

 Montanvert. I visited it for the first time in 1846. Its form 



* [From its close analogy to the instances above mentioned of the power of the 

 glacier to preserve substances buried in its mass, and to restore them years later to 

 open day, I may here record a still more recent instance : On the 25th September 

 1842, I lost a geological hammer, having a very peculiar shape, in a "moulin" of 

 great depth, on the level part of the glacier de 1'Lechaud, opposite to the ice cascade 

 of Talefre. It was recovered in the summer of 1857 by Mr. Alfred Wills at a point 

 " not far below the Tacul," and was at once recognised by Balmat, who accompanied 

 him, and who was with me when I lost it. Mr. Wills having kindly shown me the 

 hammer, I had no difficulty in bearing testimony to its identity. Indeed, anticipat- 

 ing its recovery, I had made a sketch of it in the journal in which I recorded its 

 loss. I should add, that the iron of the hammer was not rusted, nor the wood 

 decayed. January 1859.] 



