The appearance of the parallel roads is so extraordinary as to impress the imagination of the most unphilosophical, nay, even of the most incurious spectator. It is not therefore surprising that they should excite the admiration of the natives, in whom the progress of civilization has not yet extirpated those poetical feelings and that sense of the sublime, of which their literary relics still afford us proofs.
On each side of a long, hollow, deep valley, bounded by dark and lofty mountains, and at a great elevation, three strong lines are traced, parallel to each other and to the horizon, the levels of the opposite ones coinciding precisely with each other. So rarely does nature present us in her larger features with artificial forms, or with the semblance of mathematical exactness, that no conviction of the contrary can divest the spectator of the feeling that he is contemplating a work of art, a work, of which the gigantic dimensions and bold features appear to surpass the efforts of mortal powers. We cannot therefore wonder that the solitary and poetical Highlander, educated amid mountain storms and hourly conversant with the sublime appearances of Nature, should attribute to the ideal and gigantic beings of former days a work which scorning the mimic efforts of the present race, marches over the mountain and the valley, holding its undeviating course over the impassable crag, and the destroying torrent.
But it is the duty of the philosopher to investigate causes. I purpose therefore to give as ample and detailed a description as I was able to draw up, of the appearances themselves, and afterwards to examine the several modes of explanation which have been offered; stating the arguments for and against the different hypotheses as amply and as distinctly as I can, and deducing from the balance of probabilities such conclusions as the evidence appears to
