EXCALIBOUR

the mystic sword of the legendary King Arthur, which, according to the promise of Merlin, he received from the Lady of the Lake. At his death it was hurled into the lake by Sir Bedivere, where it was received by a hand which rose from the waters. EXCAVATOR. A machine for dig a} ging, loading, and transporting earth © used for building, the erection of; | Two kinds of excavators (es: — reservoirs, etc. have practically superseded all others:! bridge and steam-shovels. The one is on [ used in a long cutting and operates y. rails. A great bucket like a scoop has a i] i stout lever to counterbalance it when ‘ q filled with dirt. The scoop guided by is forced against the bank | the operator and by repeated thrusts is filled, then: swung around, the bottom opens and — the contents deposited in carts or on a dump. To widen an excavation another — excavator is used. This moves on rails laid near the edge of the bank, which is sloped at an angle of 45 degrees. The machine starts at the end of the cutting, where the jib is let down, so that the buckets can cut into the bank when they are dragged up, being filled with clay as they rise, and cars, or wagons are ready to remove their contents. Where rocks are encountered they are first blown to pieces by explosives. These excavators were often used in the World War to dig trenches, and build embankments for earth forts. See DREDGING.