The foundation of the whole is a stupendous group of Granite rocks, which rise in pyramidal clusters to a prodigious altitude, and overhang the sea. On one of those pyramids is situated the celebrated "_Logan Stone_," which is an immense block of Granite weighing above 60 tons. The surface in contact with the under rock is of very small extent, and the whole mass is so nicely balanced, that, notwithstanding its magnitude, the strength of a single man applied to its under edge is sufficient to change its centre of gravity, and though at first in a degree scarcely perceptible, yet the repetition of such impulses, at each return of the stone, produces at length a very sensible oscillation! As soon as the astonishment which this phenomenon excites has in some measure subsided, the stranger anxiously enquires how, and whence the stone originated--was it elevated by human means, or was it produced by the agency of natural causes?--Those who are in the habit of viewing mountain masses with geological eyes, will readily discover that the only chisel ever employed has been the tooth of time--the only artist engaged, the elements. Granite usually disintegrates into rhomboidal and tabular masses, which by the farther operation of air and moisture gradually lose their solid angles, and approach the spheroidal form. _De Luc_ observed, in the Giant mountains of Silesia, spheroids of this description so piled upon each other as to resemble Dutch cheeses; and appearances, no less illustrative of the phenomenon, may be seen from the signal station to which we have just alluded. The fact of the upper part of the cliff being more exposed to atmospheric agency, than the parts beneath, will sufficiently explain why these rounded masses so frequently rest on blocks which still preserve the tabular form; and since such spheroidal blocks must obviously rest in that position in which their lesser axes are perpendicular to the horizon, it is equally evident that whenever an adequate force is applied they must vibrate on their point of support. Although we are thus led to deny the Druidical _origin_ of this stone, for which so many zealous antiquaries have contended, still we by no means intend to deny that the Druids employed it as an engine of superstition; it is indeed very probable that, having observed so uncommon a property, they dexterously contrived to make it answer the purposes of an ordeal, and by regarding it as the _touchstone_ of truth, acquitted or condemned the accused by its motions. Mason poetically alludes to this supposed property in the following lines. "Behold yon huge And unknown sphere of living adamant, Which, pois'd by magic, rests its central weight On yonder pointed rock: firm as it seems, Such is its strange, and virtuous property, It moves obsequious to the gentlest touch Of him, whose heart is pure, but to a traitor, Tho' e'en a giant's prowess nerv'd his arm, It stands as fix'd as Snowdon."