It may not, therefore, be altogether profitless or unnecessary to review briefly the nature of the three great offices which mountain ranges are appointed to fulfil, in order to preserve the health and increase the happiness of mankind. Their first use is, of course, to give motion to water. Every fountain and river, from the inch-deep streamlet that crosses the village lane in trembling clearness, to the massy and silent march of the everlasting multitude of waters in Amazon or Ganges, owe their play, and purity, and power, to the ordained elevations of the earth. Gentle or steep, extended or abrupt, some determined slope of the earth's surface is of course necessary before any wave can so much as overtake one sedge in its pilgrimage; and how seldom do we enough consider, as we walk beside the margins of our pleasant brooks, how beautiful and wonderful is that ordinance, of which every blade of grass that waves in their clear water is a perpetual sign--that the dew and rain fallen on the face of the earth shall find no resting-place; shall find, on the contrary, fixed channels traced for them from the ravines of the central crests down which they roar, in sudden ranks of foam, to the dark hollows beneath the banks of lowland pasture, round which they must circle slowly among the stems and beneath the leaves of the lilies; paths prepared for them by which, at some appointed rate of journey, they must evermore descend, sometimes slow, and sometimes swift, but never pausing; the daily portion of the earth they have to glide over marked for them at each successive sunrise, the place which has known them knowing them no more, and the gateways of guarding mountains opened for them in cleft and chasm, none letting them in their pilgrimage; and, from afar off, the great heart of the sea calling them to itself! "Deep calleth unto deep." I know not which of the two is the more wonderful,--that calm, gradated, invisible slope of the champaign land, which gives motion to the stream; or that passage cloven for it through the ranks of hill, which, necessary for the health of the land immediately around them, would yet, unless so supernaturally divided, have fatally intercepted the flow of the waters from far-off countries. When did the great spirit of the river first knock at these adamantine gates? When did the porter open to it, and cast his keys away for ever, lapped in whirling sand? I am not satisfied--no one should be satisfied--with that vague answer, The river cut its way. Not so. The river _found_ its way. [22]I do not see that rivers in their own strength can do much in cutting their way; they are nearly as apt to choke their channels up as to carve them out. Only give a river some little sudden power in a valley, and see how it will use it. Cut itself a bed? Not so, by any means, but fill up its bed; and look for another in a wild, dissatisfied, inconsistent manner,--any way rather than the old one will better please it; and even if it is