Page:The New International Encyclopædia 1st ed. v. 12.djvu/280

From Wikisource
Jump to navigation Jump to search
This page needs to be proofread.
*
254
*

LIGHTHOUSE. 254 LIGHTHOUSE. ern Lights. and the Irish lights .ire under the care of the Corporation for Preserving and Inijjrov- ing the Port of Dublin, wliith is cuninioiily called the Ballist Hoard. The fund with wliiuh these boards cany on their work is provided by the one-half penny per ton due char^'cd every vessel at each time" it passes the lighthouse. In the United Slates the construction and maintenance of lighthouses is in charge of the Lighthouse Board (q.v.). Ancient Lighthouses. The oldest lighthouses known were the towers built by the Lyliians and by the C'ushites of Lower Kgypt. The light con- sisted of burning fuel in a brazier hung from a pole projecting from the tower toward the sea. The Komaiis built many line liglit towers in Italy. bil comparativelv little is known about their construction and dimensions. Perhaps the most famous tower of antiquity was that erected on the island of Pharos near Alexandria about B.C. 2S.J. The Romans built light-towers at Dover and IJoulouiie on the English Channel. Little is known of the Dover tower. Init the liouluLMie tower was a masonry structure octagonal in plan. 1!I2 feet in circumference and 200 feet high. It was built in twelve stories, each three feet less in diameter than the one beneath it. The rock on which this lighthouse was situated was un- dermined by the waves and fell, with the light- house, between 1040 and l(i-15, after the light had guided mariners for probably 1450 years. Towers of later mediicval times which are de- serving of nu^ntion are the Torre del ('a])0. near Genoa, first built in 11.3!). removed in 1.t12 and rebuilt in 104.'): the Pharos of Metoria. built liy the Pisans in 1154 and several times destroyed and rebuilt; and the Tower of Cordouaii. situ- ated at the mouth of the Gironde and finished in IGIO. These are only a few examjiles of ancient lighthouses, but they indicate quite veil the general character of these early works; viz., towers of masonry on the tops of which were built fires to serve as lights. ^[onER^• LiGHTHOVSES. Modern lighthouses may reasonably be said to date from the con- struction of the Erhlystonc Ufililhuiiff by .John Smeaton in 1750-1750. The Eddystonc rocks are a particularly dangerous reef lying in the Eng- lish Channel about 14 luilcs from Plymouth, England. Smeaton's Eddystonc lighthouse was a circular masonry tower broad at the base and narrowing by a cur"e to a slender waist at the base of the lantern-housing. The masonry of the tower was a very intricate piece of dimension stone masonry, the stones being dovetailed to- gether in such a way as to make each course practically a single stone. The height of the iiiasoniT structure to the focal plane of the lan- tern was 72 feet. In 1877 work was begun on a new Eddystonc lighthouse to replace Smeaton's, which was not h.igh enough to keep the waves from dashing over the lantern, and which, more- over, had become endangered by the undermining of the natural rock. In the new structure the tower was made cylindrical to a height of two and one-half feet above the highest tides and di- niinisliing in size above this level. It was made 1,32 feet high from high-water level to the focal plane of the lantern, the masonry being of di- mension stones cut so as to interlock and further held together by bronze bolts. The new light- house was completed in 1SS2. Faulty as Smeaton's design was in certain respects, it .served as a model for lighthouse con- struction in nuisoim- which has been followed in its general features ever since. Service Room Fig. 1. VEKTICAL 8ECTI0X 8HOWIXO INTERIOR OF NEW EDDY- STONE LIGHTHOUSE. The Bell Rock lighthouse, off the east coast of Scotland, is built upon a reef of rocks in the German Ocean, II miles from the coast, nearly opposite the Firth of Tay. The rock upon which it stands is red sandstone from 12 feet to 15 feet below spring tide, with from 2 feet to 4 feet ex- posure at low tide. The tower is also of sand- stone, but the facing masonry for a hciglit of 30 feet is granite. It was designed by the cele- brated engineers Robert Stevenson and .Tohn Ren- nie. and was modeled after the Eddystonc light- house of Smeaton. Its diameter at the base Is 42 feet and at the top beneath the cornice it is 15 feet. The stonework is 102Vi feet high and the top of the lantern is 1 15 feet high. Work was begun in 1S07 and finished in 1810. The Sker- ryvore lighthouse, off the west coast of Scotland, is built upon a cluster of rocks, the largest of