344 



ENGINEERING. 



Smeaton had to employ sailing craft to convey 

 his material from Milbray to the rock, which 

 sometimes in unfavorable weather could not 

 approach the rock for days together, the ma- 

 terial for the new structure is brought to Ed- 

 dystone in a twin-screw steamer, whose load 

 is 120 tons, which makes the passage from 

 Oreston in a little more than an hour; the 

 stones are loaded and unloaded by means of a 

 pair of double-barrel steam-winches, and are 

 raised into position by another winch on the 

 rock. The machinery of the steamer also serves 

 to pump out the water from the foundation at 

 every tide. The rock-drill used in excavating 

 the foundations can do as much work in an hour 

 as ten of Smeaton's Cornish tinners with their 

 jumpers. By comparing the time required in 

 completing Smeaton's Eddystone Lighthouse 

 with that spent on the Wolf Lighthouse, built 

 in 1869, it appears that it took Smeaton six 

 and a half times as long to accomplish a given 

 amount of labor as it takes an engineer of the 

 present day. The most important advances, 

 however, which have been made in lighthouse 

 engineering since Smeaton's day, are in the 

 illuminating facilities. The old lantern was of 

 the square type, with heavy sash-bars which 

 intercepted nearly half of the light. Until 

 quite lately this kind of lantern was still in use 

 in the lighthouse service of the United States. 

 Considerable improvements were made from 

 the use of inclined framing and other expedi- 

 ents for obviating the obstruction of the frame, 

 by Stevenson and Walker, and in 1864 the type 

 of lantern now universally adopted in British 

 lighthouses was invented; this is the helically 

 framed lantern, which, besides being optically 

 perfect and ppssessing a maximum of strength^ 

 casts no shadow which is distinguishable at a 

 distance of over a hundred feet. The 24 tallow 

 candles, of 67-candle power, which were first 

 used in Smeaton's tower, are now replaced by 

 the 4-wick Trinity House lamp with an illu- 

 minating power of 7,325 standard candles, and 

 in the new tower still stronger illumination can 

 be used. 



An iron pier constructed by the Ocean Nav- 

 igation and Pier Company, of which Jacob 

 Lorillard is president, at West Brighton, Coney 

 Island, near New York, was erected under the 

 superintendence of Messrs. Maclay and Davies. 

 It starts at high-water mark, and extends out- 

 ward 1,000 feet; it is 50 feet in width, with 

 enlargements 100 feet wide at the shore end, 

 the center, and the bulkhead. It is double- 

 decked, and has an iron substructure. The 

 whole is supported by tubular wrought-iron 

 piles of 9 inches diameter, the wall being half 

 an inch thick. These columns are placed in 

 rows 20 feet apart longitudinally and 16 feet 

 8 inches apart laterally. A circular cast-iron 

 disk, 2 feet in diameter, sunk 15 or 20 feet in 

 the sand, affords a base for each pile to rest 

 upon. The jet-water system was used in driv- 

 ing ^the piles. At the top of the columns iron 

 capitals are bolted on, supporting 15 - inch 



wrought-iron beams bolted together. These 

 uphold the superstructure. Heavy horizontal 

 struts are bolted to the beams transversely, 

 and diagonal rods 1 inch in diameter brace the 

 structure. The entire structure is supported 

 by 260 iron pillars. The landing-stage is on 

 the lower deck, and is guarded by heavy oaken 

 fenders. 



A strong iron tubular pier has been erected 

 at Long Branch. At the end of this new pier, 

 which is about 860 feet long, there is a depth 

 of 22 feet at dead low water. The pier is sup- 

 ported by tubular iron piles 6 inches in diam- 

 eter for the first 150 feet from the shore, and 

 then gradually increasing to 12 inches in diam- 

 eter at the end. They are driven into the 

 sand to the depth of from 14 to 17 feet. The 

 pier is 25 feet wide in some parts and 50 feet 

 in others. An approach 94 feet in length leads 

 down to it. The pier is floored with ash, 

 which it is proposed to remove at the end of 

 every watering season, to allow the waves to 

 flow freely among the iron supports without 

 damage. 



The large blocks of stone with which the 

 lower ends of the Mississippi jetties were 

 capped have proved entirely insufficient to 

 withstand the tremendous force of the waves. 

 Although they weighed one or two tons each, 

 the first gale swept them all away. This has 

 necessitated a supplementary labor, which has 

 been accomplished in a way that will obviate 

 all necessity of repeating it. As there was no 

 available rock for the purpose within five hun- 

 dred miles, it was decided to cap the jetties 

 with blocks of concrete. Finely broken rock 

 was brought down from the neighborhood of 

 Rose Clare on the Ohio River, and, with the 

 addition of sand, gravel, and Portland cement, 

 was molded into huge blocks of concrete on 

 the jetties. These are the largest blocks of 

 concrete ever used for such a purpose, some of 

 them being nearly double the weight of the 

 largest masses of artificial stone employed in 

 the great Cherbourg breakwater. The pro- 

 portion of the ingredients was 15 parts of the 

 broken stone, 4'38 parts of gravel, 8'28 parts 

 of sand, and 3 parts of cement, which were 

 mixed with 10J per cent, of water. It was 

 decided to be necessary to cap the last 3,800 

 feet of the east jetty and the last 2,800 feet of 

 the west jetty with solid blocks of this mate- 

 rial weighing from 25 to 75 tons apiece. The 

 materials are mixed by steam in revolving iron 

 boxes, and immediately dumped into the molds 

 and left to harden. 



On the 18th of October, 1879, the new float- 

 ing basin of the Bordeaux docks, which has 

 been three years in construction and has cost 

 three millions of dollars, was formally opened. 

 The basin, fed with water from the Garonne 

 and from a very deep artesian well, is 100,000 

 square metres in area and 10 metres deep. It 

 was made in a marshy spot, where it was ne- 

 cessary to sink solid blocks of masonry to a 

 depth of 12 metres in order to construct the 



