Indeed, unless the "crust" of our earth was of great thickness we should be subject to perpetual earthquakes. No doubt these are far more frequent than is generally supposed; indeed, with our improved instruments it can be shown that instead of occasional vibrations, with long intermediate periods of rest, we have in reality short intervals of rest with long periods of vibration, or rather perhaps that the crust of the earth is in constant tremor, with more violent oscillation from time to time. It appears, moreover, that earthquakes are not generally deep-seated. The point at which the shock is vertical can be ascertained, and it is also possible in some cases to determine the angle at which it emerges elsewhere. When this has been done it has always been found that the seat of disturbance must have been within 30 geographical miles of the surface. Yet, though we cannot connect volcanic action with the central heat of the earth, but must regard it as a minor and local manifestation of force, volcanoes still remain among the grandest, most awful, and at the same time most magnificent spectacles which the earth can afford. FOOTNOTES: [38] Ruskin. [39] _The Glaciers of the Alps._ [40] Ossian. [41] Bullar, _Azores_. [42] Tennyson. [43] See especially Heim's great work, _Unt. ue. d. Mechanismus der Gebirgsbildung_. [44] In the last 150 years more than 1000 are recorded. [45] _Letters from High Latitudes._ [46] _Glaciers of the Alps._ [47] _Mountaineering in 1861._ CHAPTER VII WATER Of all inorganic substances, acting in their own proper nature, and without assistance or combination, water is the most wonderful. If we think of it as the source of all the changefulness and beauty which we have seen in the clouds; then as the instrument by which the earth we have contemplated was modelled into symmetry, and its crags chiselled into grace; then as, in the form of snow, it robes the mountains it has made, with that transcendent light which we could not have conceived if we had not seen; then as it exists in the foam of the torrent, in the iris which spans it, in the morning mist which rises from it, in the deep crystalline pools which mirror its hanging shore, in the broad lake and glancing river, finally, in that which is to all human minds the best emblem of unwearied, unconquerable power, the wild, various, fantastic, tameless unity of the sea; what shall we compare to this mighty, this universal element, for glory and for beauty? or how shall we follow its eternal cheerfulness of feeling? It is like trying to paint a soul.--RUSKIN. [Illustration: RYDAL WATER. _To face page 251._] CHAPTER VII WATER In the legends of ancient times running water was proof against all sorcery and witchcraft: No spell could stay the living tide Or charm the rushing stream.[48] There was much truth as well as beauty in this idea.