412 An Account of the Logan Rock. - [June, 



and since such spheroidal blocks must obviously rest in that 

 position in which their lesser axes are perpendicular to the hori- 

 zon, it is equally evident that whenever an adequate force is ap- 

 plied 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." 



The rocks are covered with a species of Byssus long and 

 rough to the touch, forming a kind of hoary beard ; in many 

 places they are deeply furrowed, carrying with them a singular 

 air of antiquity, which combines with the whole of the romantic 

 scenery to awaken in the minds of the poet and enthusiast the 

 recollection of the Druidical ages. The Botanist will observe 

 the common Thrift (Statice Armeria) imparting a glowing tinge 

 to the scanty vegetation of the spot, and by growing within the 

 crevices of the rocks, affording a very picturesque contrast to 

 their massive fabric. Here too the Damns Mantimm, or wild 

 carrot ; Sedum Telephium, Saocifraga Stellaris, and Asplenium 

 Marinum, may be found in abundance. 



The granite in this spot is extremely beautiful, on account of 

 its porphyritic appearance ; the crystals of felspar are numerous 

 and distinct ; in some places the rock is traversed by veins of 

 red felspar, and of black tourmaline, or schorl, of which the 

 crystalline forms of the prisms^ on account of their close aggre- 

 gation, are very indistinct. Here mav also be observed a con- 

 temporaneous vein of schorl rock in the granite, nearly two feet 

 wide, highly inclined and very short, and not having any distinct 

 walls. On the western side of the Logan rock is a cavern, 

 formed by the decomposition of a vein of granite, the felspar of 

 which assumes a brilliant flesh-red, and lilac colour; and where 

 it is polished by the sea, exceeding even in beauty the Serpen- 

 tine caverns at the Lizard. 



Mr. Majendie observed in this spot numerous veins of fine- 

 grained granite, which he is inclined to consider as cotempora- 

 neous ; he algo observed what, at first sight, appeared to be frag- 





