DOCK. 341 DOCK. agjiresale area of about 124 acres; and tlic acres of low marsh land were converted into a Milhvall Docks, with an area of about 35 acres, basin. Excavation over the whole 40 acres was The Liverpool dock system is one of the largest done mainly with dred;;inf; machines and was and best in the world, its construction was be- carried to a depth of 20 feet below low-water
- un nearly a century and a half ago, but its mark. The outer inclosure was made with piers
principal develop- ment lias oc- curred durinj; the last titty years of the nineteenth century. In 1S.57 the Murray Docks and Harbor Board by an Act of Par- liament was given the control and , manajienientof all *_ the docks of Liv- 2^ erpoiil. including ' those of Birken- head on the oppo- site side of the river. In 1898 this board had charge of 07 wet docks and 2.3 dry docks, having a frontage of about seven miles. ' The dock area if about 1100 acres; the largest docks are the Canada, about 18 acres; the Langton, 18% acres: and the Alexanilra, IT^.i acres. The total cost of the Liverpool dock system was estimated in 1808 to have been $200,000,000. Among the other British ports which have notable docks are: Cardiff. Penarth, Barrow, Kingston, Leith,' Belfast, and Tyne. On the Continent the docks at Havre, France, are particularly notable: they graving docks. The Kingston and the Queen's consist of two principal basins, having an area Docks in Glasgow, Scotland, are good examples of about 171 acres. of tidal docks. The Kingston Dock has an area of 5V4 acres, a quav space of 24il0 feet, and a depth of about 24 feet ; the Queen's Dock has an area of 34 acres, a quay space of 10,- OOO" feet, and a depth of from 27 to 30 feet, A Dry Dock is a masonry or timber - lined ba- sin connecting with the harbor waters and hav- ing approximate- ly the shape of a ship's hull. Into Plan MASONRY DEY DOCK, BOSTON" XAVY-VARD. of crib-work, consisting of timber filled with stone, which were sunk into trenches 30 feet below high-water mark. The cribs were 2,5 feet thick at the base and were placed 1,50 feet apart, that being the width of the pier. In the basin are a number of wooden piers where vessels are loaded. Upon the crib-work piers large stone warehouses are built. On the inland side is the conunercial wharf. 2000 feet in length. The Erie Basin, near the Atlantic Dock, contains two DOCKS AT BAVBE, FRANCE. TiD.L Docks are adapted to locations where which a vessel can be floated and which can the range of the tides is small, as along the Atlantic and (iulf coasts of the United States, where this range varies from 9 feet, on the New England coast, to about 2 feet at Galveston, Tex., at the Mediterranean ports, at Glasgow, Scotland, and Hamburg, Germany, The almost universal form of dock in America is a series then be closed and emptied so as to leave the bot- tom of the vessel dry and available for cleaning and repairs. In Europe it is the almost uni- versal practice to line dry docks with masonrj'. In the United States the prevailing jiractice has been to build timber dry docks, although there has recently been a reaction against of rectangular water-spaces between piers which timber docks. At the present time a timber project out from the bulkhead line, although dock can be built for about 25 per cent, less tidal basin docks are found in a few places. The money, but engineers are quite unanimous in Atlantic Docks and the Erie Basin in Brooklyn opinion that the greater cost of masonry docks are examples. The Atlantic Docks were com- is compensated for by their lower cost for re- menced in 1841 and were several years in eon- pairs and their far greater durability, strength, stmction. More than 200 acres of land were and safety. The following figures show the secured bj- the Atlantic Dock Company, and 40 leading dimensions of some of the more impor-
