Arnold Guyot. 363 



Switzerland — had led him to the bold conclusion ; and he was 

 full of his new ideas when he met his old companion. He 

 urged Guyot, who hesitated at accepting his views without 

 examination, to study the facts ; and obtained the promise that 

 he would visit the glaciers that summer. 



In his memoir of Agassiz, Guyot states that his six weeks of 

 investigation that season in the central Alps (nearly two years 

 before Agassiz commenced his investigations on the glacier of 

 the Aar) were fruitful beyond expectation. He says, that from 

 the examination of the glaciers of the Aar, Rhone, Gries, 

 Brenva and others, he learned (1) the law of the moraines ; 

 (2), that of the more rapid flow of the center of the glacier than 

 the sides ; (3), that of the more rapid flow of the top than the 

 bottom ; (4), that of the laminated or ribboned structure (" blue 

 bands ") ; and (5) that of the movement of the glacier by a 

 gradual molecular displacement, instead of by a sliding of the 

 ice- mass as held by de Saussure. 



The facts and conclusions were communicated to the Geo- 

 logical Society of France at a meeting at Porrentruy in Sep- 

 tember, 1838. The communication is mentioned in the Bulletin 

 of the Society for that year;* but no report of it is given, 

 because the manuscript remained in his hands unfinished in 

 consequence of his protracted illness the winter following. 

 The portion then finished (which afterward was withheld from 

 publication because, by special arrangement between them, 

 Agassiz, in 1840, entered upon the special study of the glacier, 

 and Guyot on that of the Swiss erratic phenomena, for their 

 separate parts of a general survey) has recently been printed in 

 volume xiii (1883) of the Bulletin of the Neuchatel Society of 

 Natural Sciences. 



In 1842 this manuscript was deposited, by motion of Agassiz, 

 in the archives of the Neuchatel Society, and in 1848 it was 

 withdrawn by Guyot when he left for America. It is to be 

 regretted that publication was not substituted in 1842 for 

 burial. Its recent publication was made by the request of 

 Guyot early in 1883 lrom a certified copy of the original 

 manuscript. 



This paper gives the facts on which Guyot based his conclu- 

 sions; and since these conclusions comprise some of the most 

 important of the views now accepted relating to glacier motion 

 and structure, and antedate the observations of Agassiz, Rendu 

 and Forbes, they have special interest. 



The fact of a less rapid movement of the bottom ice than the top, 



owing to friction, he ascertained by the observation that in 



glaciers of steep descent, like the Rhone at its rapids, and the 



Gries. the transverse crevasses and the masses they cut off are 



* Volume ix, page 407. 



