550 THE LIFE OF JAMES 1). FORBES. [APFKXK 



1 1 have thus abundant evidence, independent of your ample testimony, to 

 show that, at the date I have mentioned, my friend Agassiz was unaware of 

 the general occurrence of the ribbonsd structure, through the mass of glaciers ; 

 and, in writing to him some days ago, mentioned my conviction that the 

 discovery, certainly the most important of the recent ones, was due to you. 

 I shall be glad to find that, as I believe is the c^e, M. Desor alone, and not M. 

 Agassiz, could call it in question.' 



The ' stratification ' alluded to at the close of the first para- 

 graph of the preceding letter, refers to the twisted planes of 

 structure which I have described in my paper, and which 

 are, in fact, continuous with the veins which, throughout the 

 greater mass of the glacier, run parallel to its sides, when 

 these sides are steep and continuous. The complex form of 

 the surfaces of the shells into which a glacier is divided by 

 these bands of compact and friable ice, 1 was first able to dis- 

 cover, during a visit to the glacier of the Rhone, on the 23rd 

 August, 1842. I was accompanied by Mr. Heath and Mr. Cal- 

 verley Trevelyan, but not by M. Agassiz or any of his party. 

 In the course of a very careful examination of the glacier, I 

 succeeded in satisfying myself completely of the conoidal form 

 of the veined surface, and in explaining the apparent frontal 

 stratification, which I have since confirmed in every point. 1 

 On our return to the Grimsel, I explained my views to M. 

 Agassiz, who copied the sketch I had made, which corresponds 

 exactly to that in the Edinburgh Philosophical Journal, January 

 1842, p. 89. A int'iitli later, I explained this system of curves 

 of structure of the glacier of the Ehone to M. Studer at Berne. 

 His penetration immediately perceived its importance, and he 

 expressed great satisfaction at the insulated fact which I had 

 pointed out to him on the glacier of the Aar being thus general- 

 ized. 2 We both agreed that its explanation must involve, in 

 a good measure, the true theory of glaciers. In a letter to 

 Professor Bronn of Heidelberg, dated 1st October, 1841, a 

 week after I had quitted Berne, M. Studer gives an accurate 

 account of my observations, being the first publication on the 

 subject. 3 



1 See Letters to Professor Jameson in this Journal for October 1842, p. 346. 



2 M. Studer, after quitting the glacier of the Aar, had recognized the 

 structure on several others in the canton of Yallais. I should add that I 

 pointed out the veined structure to M. Agassiz on the glacier of Gauli, in the 

 Urbachthal, on the 20th August, and it was afterwards noticed by both of us 

 on the Oberaar Glacier, and that of Aletsch. So that no reasonable doubt 

 remained, at least, on jny mind, that, ha\ing been observed on no less than five 

 contiguous glaciers, it was a general and not a particular phenomenon. This 

 meets M. Agassiz' statement, that I not only 'erroneously claimed the dis- 

 covery,' but ' assigned to it a generality which the facts observed by myself did 

 not at all justify.' Erf. Phil. Jour., p. 265. 



3 Leonhard's Jahrbuch, 1841. 



