18 THIRD LETTER ON GLACIERS. [1842. 



valley quite to its origin. We then crossed to the western 

 branch of the valley of Erin, by the Col de Collon or Arolla, 

 a very striking glacier pass. Thence M. Studer went to the 

 Val d'Anniviers, and rejoins me here by the way of Yisp, whilst 

 I ascended the other branch of the Eringer Thai from Evolena 

 by way of the Ferpecle glacier, and crossed over the mountains 

 to this place, by a pass higher and much longer than the Col 

 du Geant, which presents, certainly, the grandest views I have 

 hitherto met with in the Alps. I must not, however, stop to 

 describe, as my present object is to fulfil the promise in my 

 last respecting the structure of glacier ice. 



The internal veined or ribboned structure presented by all 

 glaciers in a greater or less degree, appears to be the only true 

 essential structure which they possess, and which, you will 

 recollect, I described in a paper printed in your Journal for 

 January last.* The existence of granules divided by capillary 

 fissures, as well as of large crevasses, are equally unessential to 

 glacier structure, and subordinate to the other. Whatever 

 other result may flow from the examination of glaciers this 

 summer, by the many persons who are probably at this moment 

 directing their attention to them, this, I am sure, will be ad- 

 mitted, that the veined structure is not peculiar to some glaciers, 

 as some would maintain, nor to some years, as has been alleged 

 by others ; but that it is perfectly general and systematic, having 

 one general type or form, which is varied according to external 

 mechanical circumstances. Being then the most essential and 

 intimate part of the glacier formation, as well as one of its most 

 obvious and universal features (especially on those glaciers which 

 are most commonly visited), it is equally singular that it should 

 not have been sooner noticed, or if noticed, never once alluded 

 to by the eminent and ingenious authors who have treated of 

 existing glaciers and their effects. 



With respect to the general type or form of this structure, 

 I am happy to say that I have found not the slightest reason 

 to modify the description which I have given in the paper above 



* [See page 1 of this volume.] 



