THE OCEAN'S WAVES.

Auckland Star, Volume XIX, Issue 100, 28 April 1888, Page 3 (Supplement)

THE OCEAN'S WAVES.

Exaggerated Notions as to Their

HeigSit.

It is a very common phrase to speak of the waves during a storm as "running mountains high," but this really means nothing. Accurate measurements made by Scoresby proved that during storms waves in the Atlantic rarely excoed 43 feet from hollow to crest, the distance between the crests being 560 feet and their speed 32J miles an hour. More recent observations in the Atlantic give from 44 feeb to 48 feefe as the highest measured waves, but such heights are rarely reached, and, indeed, waves exceeding 30 feet are very seldom encountered. The monsoon waves at Kurrachee breakwater works are found to dash over the wall to the depth of 13 feet, or about 40 feet above mean eea level.

The greatest heights of waves on the British coast wero those observed in Wick Bay-so famous for the exceptionally heavy seas which roll into it—being 374 to 40 feet. Green seas 25 feet deep poured over the parapet of tho breakwater at intervals of from ."even to ten minutes, each wave.it was estimated, being a mass of 40,000 tons of water, and this continuously for three days and nights. The iron lighthouse erected on the Bishop rock waa carried away by unbroken seas striking the dwelling, the floor of which was 85 feet above high water. A tower of granite was subsequently erected on the Bishop, and in 1860 the waves carried away the fog boll, weighing 300 pounds, at an elevation of 100 feet above the sea. In the Shetland islands blocks of stone have been quarried at the height of 70 to 75 feet above the mean sea level.

But these instances of fche action of tho waves during storms sink into insignificance when it is mentioned that blocks of concrete weighing 1,350 to 2,600 pounds respectively were carried away by the repeated assaults of the wild rollers of Wick Bay. The depth to which wave action extends has been differently estimated, but it varies from 70 to 150 "feet, as shellfish which are known only to live at these depths mo thrown upon the shore during heavy gales, ami it has been ascertained that shingle is moved in a depth of fifty feet. For all practical purposes, however, so far as harbour works are concerned, it is found that there is little movement of materials under eighteen to twenty feet below water, the foundations of breakwaters hitherto constructed not having been disturbed below these lovels.—" The Scotsman."