Eddystone Rocks, a reef in the English channel, 600 or 700 ft. long, off the coast of Cornwall, about 10 m. S. of the Rame head, entrance of Plymouth sound. They consist of three principal ridges, which are entirely covered at high water. The celebrated lighthouse on one of these rocks was begun in 1756 and finished in 1759. Its tower is 68 ft. high, and is surmounted by a lantern which is furnished with 16 powerful argand burners, with parabolic reflectors of silvered copper. The first lighthouse on these rocks was built in 1696-'9, of stone and timber. It was swept away in 1703, and another tower of wood was completed six years afterward. This was burned in 1755, and the present edifice was then commenced by the celebrated engineer John Smeaton. The material employed was Portland stone, encased in granite, partly quarried from the rock itself, into which the foundations were dovetailed. The violence of the swell at the lighthouse renders communication with the shore extremely difficult even in serene weather, and the sea frequently rises above the light, the strong plate glass of the lantern having been more than once broken by the waves. - See "A Narrative of the Building of Eddystone Lighthouse," by Smeaton (4to, London, 1791).
Eddystone Lighthouse (with section showing the interior arrangement).