Although I had, in my overland journey from Van Rensselaer Harbor with Mr. Wilson, in 1853, reached the face of the mer de glace, where it rested behind the lofty chain of hills which runs parallel with the axis of the continent, yet this was the first time that I had actually been upon it; and its vastness did not on the former occasion impress me as now. Even the description of the great Humboldt Glacier which I had from Mr. Bonsall, and the knowledge that I had acquired of the immense glacier discharges of the region further south, failed to inspire me with a full comprehension of the immensity of ice which lies in the valleys and upon the sides of the Greenland mountains.
Greenland may indeed be regarded as a vast reservoir of ice. Upon the slopes of its lofty hills the downy snow-flake has become the hardened crystal; and, increasing little by little from year to year and from century to century, a broad cloak of frozen vapor has at length completely overspread the land, and along its wide border there pour a thousand crystal streams into the sea.
THE GLACIER SYSTEM.
The manner of this glacier growth, beginning in some remote epoch, when Greenland, nursed in warmth and sunshine, was clothed with vegetation, is a subject of much interest to the student of physical geography. The explanation of the phenomena is, however, greatly simplified by the knowledge which various explorers have contributed from the Alps,—a quarter having all the value of the Greenland mountains, as illustrating the laws which govern the formation and movements of mountain ice, and which possesses the important advantage of greater accessibility.
It would be foreign to the scope and design of this book to enter into any general discussion of the various theories which have been put forth in explanation of the sublime phenomena, which, as witnessed in the Alpine regions, have furnished a fruitful source of widely different conclusions. It was, however, easy to perceive in the grand old bed of ice over which I had traveled, those same physical markings which had arrested the attention of Agassiz and Forbes and Tyndall, and other less illustrious explorers of Alpine glaciers; and it was a satisfaction to have confirmed by actual experiment in the field the reflections of the study. The subject had long been to me one of great interest; and I was much gratified to be able to make a comparison between the Alpine and Greenland ice. It was not difficult to read in the immense deposit over which I had walked whence came the suggestion of dilatation to Scheuchzer, or of sliding to De Saussure; or, in the steady progress of knowledge and discovery, the principles of action that are illustrated by the terms vitrious and viscous and differential motion, as applied to the Alpine ice by eminent explorers of later date.
GLACIERS.
The subject of Greenland ice is one about which there exists much popular misapprehension. As before stated, I do not here propose to enter into a minute discussion of the manner of its formation and movement, but will content myself with simply recognizing the fact, and with drawing such comparison as may be needful between the mountain ice of Greenland and similar deposits in other quarters of the world. Under this head I trust that the reader may find sufficient interest in the line of argument to follow me through a few pages, in a general review of the whole field. At a later period I will recur to some more specific details of information and discussion, as the narrative carries us to other objects of inquiry.
In order to make the subject clear, I cannot do better than to cite my illustrations from the region of the Alps, where, through a long period, earnest explorers have laboriously pursued their inquiries. One of the most important and gifted of these was M. Le Chanonie Rendu, Bishop of Annecy. This excellent and worthy man, and sincere devotee as well of science as of religion, died some seven years ago. A lifetime spent among the rugged crags and ice-cliffs of the Alpine Mountains had familiarized him with every phase of Nature in that region of sublimity and home of the wonderful. Professor Tyndall says truly of him, that "his knowledge was extensive, his reasoning close and accurate, and his faculty of observation extraordinary;" and he early brought his splendid faculties of mind and his energy of body and profound love of truth to bear upon the elucidation of those natural phenomena which were constantly exhibited in his presence. After many years of conscientious toil, he gave to the world the results of his systematic investigations in an essay which was published in the Memoirs of the Royal Academy of Sciences of Savoy, entitled, "Théorie des Glaciers de la Savoie."
ORIGIN OF GLACIERS.
I will use the information acquired from this source as the basis of my present argument,—to demonstrate, by the law as interpreted to us from the Alps by this learned priest of Annecy, how the Arctic continent receives its cloak of crystals, and how it discharges the superabundant accumulation.