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bad gone in search of it; and we read that when Alexander in rested Tyre, his works were considerably damaged by thedivers of that city. Extraordinary accounts have been givenof the length of time that the divers employed in the pearl-fishery could continue under water : and many attempts havebeen made to discover some method by which it could berendered more safe and easy. Those who dive for sponges inthe Mediterranean, derive some advantage by carrying downsponges dipt in oil in their moutlis ; but this, from the smallquantity of air contained in the pores of a sponge, can notafford any great assistance.

The earliest information we have of any machine resem-bling the dwmg-btU,'ia to be found in Aristotle , who informsus of a kind of kettle, by which the divers could supplythemselves with fresh air under water; and it is related byJerome that Alexander the Great entered into a machine calleda colympha, having n glass window to it, in which he de-scended to the bottom of the ocean. The application of thediving-bell in Europe is first noticed by John Tasuier, whohad a place at court under the Emperor dairies V., wliom heattended on his voyage to Africa : he relates that he saw atToledo , in Spain , in the year 1538, and in the jiresence of theEmperor and several thousand spectators, two Greeks letthemselves down under water, in a large inverter! kettle, witha light burning, and rose up again without being wet. Afterthis period the use of the diving-hell became generally known,and is noticed in the works of Sir Francis Bacon .

In the year 1687, the sum of s£2(X>,000 was recovered froma Spanish ship which had been wrecked on the coast ofHispaniola , by means of a diving bell, invented by WilliamPhipps, the son of a blacksmith in America , who was afterwards knighted. Several improvements in the invention havebeen since made by IJulley, Spalding, Joachim and others, bymeans of which a person may now by practice remain upwardsof an hour under water.