220 Professor Agassiz oti the Glacial Theory. 



posed that in these islands, equally remote from the glaciers 

 of the Alps and the ice of the north, traces of the action of ice 

 should have been found ! And, nevertheless, all the pheno- 

 mena which indicate the former existence of glaciers are there 

 just a? evident, and just as well preserved, as in the neigh- 

 bourhood of the glaciers of the present day. England likewise, 

 — thanks to the activity and the zeal of her savans — already 

 possesses quite a literature on the subject of glaciers ; and it 

 would be necessary for me to cite the names of most of the 

 geologists of that country, were I to mention all the indivi- 

 duals there who have occupied themselves with this question. 



The purely theoretical part of the erratic phenomenon has 

 also attracted much attention ; and the discussions to which 

 it has given rise in many places, and particularly in the Geo- 

 logical Society of France, have contributed, on their part, to 

 render the study still more interesting, by connecting it with 

 the great problems of the cosmic system. 



Passing from the geological domain, attention oiight natu- 

 rally to be directed to the glaciers of the present day, which 

 are, in fact, the touchstone of the whole system ; for, in order 

 to be entitled to call in their intervention to explain the erra- 

 tic phenomenon, it is necessary to know, even to the most mi- 

 nute details, their actual condition, and their action on neigh- 

 bouring bodies. Now, although the researches of naturalists 

 feince the time of Scheuchzer and Saussure have made us ac- 

 quainted with the general laws which preside over their for- 

 mation and their metamorphoses, there is, nevertheless, a 

 multitude of details regarding their internal structure and 

 their modifications, as connected with the different seasons, 

 the import of which is still unknown to us ; and there is even 

 a diversity of opinion among naturalists on some of the capital 

 points. Since the publication of my Etudes siir les Glaciers^ I 

 have made many additional expeditions to the interior of glaciers 

 with the view of answering certain objections made to my theo- 

 ry by natural philosophers. I have also resided a second time 

 on the Mer de Glace of the Lauter-Aar and of the Finster-Aar, 

 in order to study the structure of the ice at all heights and in 

 all conditions of the atmosphere, and I hope to be able to con- 

 timie these same researches still longer, — ^thanks to the mu.ni- 



