THE EDDYSTONE LIGHT

Sun (Auckland), Volume IV, Issue 1042, 5 August 1930, Page 14

THE EDDYSTONE LIGHT

STONE FORTRESS OUT AT SEA ENGINEERS’ LONG BATTLE Fifty years ago the great granite squares which were to form the base of the Eddystone Lighthouse were being assembled at Plymouth. For centuries British engineers had battled with the jiroblems presented by the wicked coastline of South-west-ern ijiuglaiid. Successive edifices had bec-n swept away by the wind and waves as though they had been built of straw. No other ocean highway in the world was hedged by a shore which called for such a number of warning lights. The first Eddystone, built of wood, was greeted in the year 1700. Winstanley, the engineer who designed it. was himself killed when it was carried awaj’ three years later. In 1709 a bigger and stronger wooden structure was put up by Itudyarcl. It caught fire and was destroyed forty-six years later. Smeaten built the third, takiug as his model the trunk of an oak tree. He used granite and Portland stone, and for over ten years his creation defied the gales of the Cornish coast. In IS7S work was commenced on the present building, of which Sir James Douglas was the designer, and it was completed lour years later. Work on the foundations could only be carried out at low water. Great steel rods were driven deep into the rocks. On to these were skewered the massive blocks of stone which had been prepared ashore. In order to make them lock tightly together these blocks were dove-tailed. A long study of the problem of coast erosion had proved that the laying of rectangular stones upon each other, in the ordinary way, with the use of jointing material, had not given the maximum of stability. The receding water had sucked the mortar from between the stones, leaving a space into which the oncoming waves had forced air. A sort of pneumatic action was thus set up, with the result that as the waves rolled back the sudden escape of imprisoned and compressed air actually moved the masonry.

The stone base on which the Ktklystone tower rests rears itself a full 25ft above the normal water level. Into its floor are sunk two tanks, each capable of storing 5,000 gallons of fresh water. The entrance to the tower is guarded by two doors, one of gunmetal, which weighs a ton, and an inner one of solid teak. The walls of the tower, which is built to stand a wind pressure of 7,7001 b to the square foot, are Sft thick, and the tower itself consists of 2,000 blocks of granite, each weighing two tons. Although permanency was the main thing aimed at, no fault can be found with Eddystone Lighthouse from an architectural point of view. Even Its contour is rhythmic and imposing. As far as the navigator is concerned, however (and he is the person chiefly interested), the light is the vital thing. Since the age of Ptolemy 11., who caused to be built on the Island of Pharos, off Alexandria, the first of all real lighthouses, the matter which has chiefly engaged the attention of scientists has been the intensification and mobility of the light. The very earliest type of light used was an open wood fire, burning upon a coastal eminence. The brazier gave place in time to tho tallow candle. Gas eventually superseded the candle, just as gas is now being ousted by electricity. During the last 100 years most progress has been made in connection with the diffusion of the available light, and the experiments made by engineers have had as their main object the ideal arrangement of reflectors and the greatest possible range of the beam. Trinity House is, of course, the authority responsible for the lights which are dotted along the shores of Britain. Venerable as Trinity House may be, it Is alive today to its onerous responsibilities as ever it was. Now that the bulk production of electricity is bringing down the price of light, the “House” is steadily engaged in the electrification of all its lightships and lighthouses. Eddystone, partly because of its remoteness and consequent inaccessibility, has not yet had electricity installed, but it is “on the list.” St. Catherine's Point, which warns ships of the Atherfield Ledge, off the Isle of Wight, was electrified 30 yeggs ago. Owing to the curvature of the earth’s surface a ground light cannot be picked up at a distance much greater than IS miles, but what is called the “loom” of St. Catherine’s light can, on a clear night, be seen quite plainly in the Channel Islands, 70 miles away. Year by year the number of disasters at sea become steadily less, and it is to the fact that Trinity House never'wearies in its task of safeguarding the sailor that this satisfactory state of affairs is largely due. Much as Britain owes to her indomitable mariners, they, in their turn, are loud in proclaiming their gratitude to the authorities ashore, whose principal job it is to give them safety on their coastwise voyages.