Great revelations of nature, of course, never fail to impress in one way or another, and I was no stranger to moods of the kind. Mountains overawe and oceans terrify, while the mystery of great forests exercises a spell peculiarly its own. But all these, at one point or another, somewhere link on intimately with human life and human experience. They stir comprehensible, even if alarming, emotions. They tend on the whole to exalt.