It is, I am sorry to say, just forty years (some day last month) since I first saw the Bernese Alps from above Schaffhausen. Since that evening I have never let slip a chance of knowing anything definite about glaciers and their ways; and have watched the progress of knowledge, and the oscillations of theory, on the subject, with an interest not less deep, and certainly more sincere, than it would have been if my own industry had been able to advance the one, or my own ingenuity to complicate the other. But only one great step in the knowledge of glaciers has been made in all that period; and it seems the principal object of Professor Tyndall's book to conceal its having been taken, that he and his friends may get the credit, some day, of having taken it themselves. I went to the University in 1836, and my best friend there, among the older masters, Dr. Buckland, kept me not ill-informed on my favourite subject, the geological, or crystallogical, question. Nearly everything of which Professor Tyndall informs his courageous readers was known then, just as well as it is now. We all,--that is to say, all geologists of any standing, and their pupils,--knew that glaciers moved; that they were supplied by snow at the top of the Alps, and consumed by heat at the bottom of them; that there were cracks all through them, and moraines all down them; that some of their ice was clear, and other ice opaque; that some of it was sound, and some rotten; and that streams fell into them at places called mills, and came out of them at places called grottoes. We were, I am sorry to say, somewhat languidly content with these articles of information; we never thought of wading "breast-deep through snow" in search of more, and still less of "striking our theodolites with the feelings of a general who had won a small battle." [93] Things went on thus quietly enough. We were all puzzled to account for glacier motion, but never thought of ascertaining what the motion really was. We knew that the ice slipped over the rocks at some places, tumbled over them at others; gaped, or as people who wanted to write sublimely always said, yawned, when it was steep, and shut up again when it was level. And Mr. Charpentiêr wrote a thick volume to show that it moved by expansion and contraction, which I read all through, and thought extremely plausible. But none of us ever had the slightest idea of the ice's being anything but an entirely solid substance, which was to be reasoned about as capable indeed of being broken, or crushed, or pushed, or pulled in any direction, and of sliding or falling as gravity and smooth surfaces might guide it, but was always entirely rigid and brittle in its substance like so much glass or stone.