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BOMB

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Originally appearing in Volume V04, Page 182 of the 1911 Encyclopedia Britannica.
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BOMB , a See also:

term formerly used for an explosive See also:shell (see AMMuNrT1oN) fired by See also:artillery. The word is derived from the Gr. fbµ(3os, a hammering, buzzing See also:noise, cf. " See also:bombard " (q.v.). At the See also:present See also:day it is most frequently used of a shattering or incendiary See also:grenade, or of an explosive See also:vessel actuated by See also:clock-See also:work or trip mechanism, employed to destroy See also:life or See also:property. In See also:naval warfare, before the introduction of the shell See also:gun, ex-plosive projectiles were carried principally by See also:special vessels known as bomb-vessels, bombards or, colloquially, bombs. In See also:geology, the name "bomb " is given to certain masses of See also:lava which have been hurled forth from a volcanic vent by explosive See also:action. In shape they are spheroidal, ellipsoidal or discoidal; in structure they may be solid, hollow or more or less cavernous; whilst in See also:size they vary from that of a See also:walnut to masses weighing several tons. It is generally held that the See also:form is partly due to rotation of the See also:mass during its aerial See also:flight, and in some cases the bomb becomes See also:twisted by a gyratory See also:movement. According, however, to Dr H. J. See also:Johnston-Lavis, many of the so-called bombs of See also:Vesuvius are not projectiles, but merely globular masses formed in a stream of lava; and in like manner See also:Professor J. D.

See also:

Dana showed that what were regarded as bombs in See also:Hawaii are in many cases merely lava-balls that have not been hurled through the See also:air. Certain masses of See also:pumice ejected from Vulcano have been called by Johnston-Lavis " See also:bread-crust bombs," since they present a coating of See also:obsidian which has been See also:bent and cracked in a way suggestive of the crust of a See also:roll. It is probable that here the See also:acid magna was expelled in a very viscous See also:condition, and the crust which formed on cooling was burst by the See also:steam from the occluded See also:water. Some of the bombs thrown out during See also:recent eruptions of See also:Etna consist of See also:white granular See also:quartz, encased in a See also:black scoriaceous crust, the quartz representing an altered See also:sandstone. The bombs of granular See also:olivine, found in some of the tuffs in the See also:Eifel, are represented in most See also:geological collections (see See also:VOLCANO).

End of Article: BOMB

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