I know no other waters to be compared with them;--such streams can only exist under very subtle concurrence of rock and climate. There must be much soft rain, not (habitually) tearing the hills down with floods; and the rocks must break irregularly and jaggedly. Our English Yorkshire shales and limestones merely form--carpenter-like--tables and shelves for the rivers to drip and leap from; while the Cumberland and Welsh rocks break too boldly, and lose the multiplied chords of musical sound. Farther, the loosely-breaking rock must contain hard pebbles, to give the level shore of white shingle, through which the brown water may stray wide, in rippling threads. The fords even of English rivers have given the names to half our prettiest towns and villages;--(the difference between ford and bridge curiously--if one may let one's fancy loose for a moment--characterizing the difference between the baptism of literature, and the edification of mathematics, in our two great universities);--but the pure crystal of the Scottish pebbles, [68] giving the stream its gradations of amber to the edge, and the sound as of "ravishing division to the lute," make the Scottish fords the happiest pieces of all one's day walk. "The farmhouse itself was small and poor, with a common kailyard on one flank, and a staring barn of the doctor's ('Douglas') erection on the other; while in front appeared a filthy pond, covered with ducks and duckweed, [69] from which the whole tenement had derived the unharmonious designation of 'Clarty Hole.' But the Tweed was everything to him: a beautiful river, flowing broad and bright over a bed of milk-white pebbles, unless where, here and there, it darkened into a deep pool, overhung as yet only by the birches and alders which had survived the statelier growth of the primitive forest; and the first hour that he took possession he claimed for his farm the name of the adjoining ford." [70] With the murmur, whisper, and low fall of these streamlets, unmatched for mystery and sweetness, we must remember also the variable, but seldom wild, thrilling of the wind among the recesses of the glens; and, not least, the need of relief from the monotony of occupations involving some rhythmic measure of the beat of foot or hand, during the long evenings at the hearth-side.