TIDES AND OCEANIC HIGHWAYS. 367 



Straits. With reference to the immense body of water which is constantly pouring into 

 the Mediterranean from the Atlantic, there is no necessity to have recourse to an under- 

 current conveying it back into the ocean to account for its disposal ; for a considerable 

 portion may be returned there by the lateral currents, while an enormous evaporation 

 expends the rest. We have no evidence whatever of the existence of such a phenomenon 

 as the superior and inferior stratum of the same volume of water flowing in opposite 

 directions. Ray long ago remarked : " I do not understand how waters can run back- 

 ward and forward in the same channel at the same time. For, there being but one decli- 

 vity, this is as much as to affirm that a heavy body should ascend. It is a crossing of 

 proverbs, avu Trora/^wv, making rivers ascend to their fountains, affirming that to be done 

 which all the world hath hitherto looked upon as absurd and impossible." 



Currents pursuing an inverse course sometimes meet and conflict ; and when this 

 occurs in narrow channels, it renders their passage troublesome and dangerous to the 

 mariner. When two currents, thus meeting together, are nearly of equal force, they 

 often cause eddies or whirlpools, of which the Maelstrom, off the coast of Norway, is a 

 remarkable example. Its influence is felt for more than nine miles, and its power is such, 

 that vessels drawn into its grasp have been unable to extricate themselves, and have perished 

 in its vortex. In a storm, the roar of the contending waters is heard through a wide area 

 upon the surface of the deep. Charybdis, in the straits of Messina, is another instance, 

 so famed in antiquity, with its companion Scylla, for offering perils to the ancient navi- 

 gators. Homer pourtrays Scylla as a rock so lofty that its summit is continually cloud- 

 capt, and so steep, smooth, and slippery, that no mortal could scale its height, though the 

 capabilities of his physical frame for the ascent were largely multiplied : 



" High in the air the rock its summit shrouds 

 In brooding tempests and in rolling clouds ; 

 Loud storms around, and mists eternal rise, 

 Beat its bleak brow, and intercept the skies. 

 When all the broad expansion, bright with day, 

 Glows with th' autumnal or the summer ray, 

 The summer and the autumn glow in vain ; 

 The sky for ever lours, for ever clouds remain. 

 Impervious to the step of man it stands, 



Though borne by twenty feet, though arm'd with twenty hands. 

 Smooth as the polish of the mirror rise 

 The slippery sides, and shoot into the skies." 



The Greek poet, and Virgil after him, personify this rock as a sea monster, lurking in 

 the darkness of a, vast cavern, surrounded by ravenous, barking mastiffs, together with 

 wolves, increasing the horror of the scene : 



" Here Scylla bellows from her dire abodes, 

 Tremendous pest ! abhorr'd by man and gods ! 

 Hideous her voice, and with less terrors roar 

 The whelps of lions in the midnight hour." 



Not less terrible is the description of Charybdis, represented by Homer as a companion 

 monster, three times in a day drinking up the water, and three times vomiting it 

 forth: 



" Beneath Charybdis holds her boisterous reign 

 'Midst roaring whirlpools, and absorbs the main ; 

 Thrice in her gulfs the boiling seas subside, 

 Thrice in dire thunder she refunds the tide." 



This language of poetical fable and exaggeration rests upon a stratum of truth. In the 

 Straits of Messina the site of Scylla on the Calabrian shore, and of Charybdis by the 



