A MAMMOTH ICEBERG.

Globe, Volume XXII, Issue 2043, 10 September 1880, Page 3

A MAMMOTH ICEBERG.

Amongst the almost countless and colossal icebergs recently reported by incoming steamers, that'encountered by the Oity of London on her last voyage, " about 1500 feet long and 300 feet high," commands special note. Ao the specific gravity of ice is so much less than that of Atlantic sea-wateritis ascertained that the portion of a berg under water is over eight times as great as that exposed to the air. This proportion is based on the supposition that the iceberg is symmetrical, but in any case we may assume that about seven eighths is submerged, and probably this particular berg could not have floated in water under 2500 feet, or 400 fathoms in depth. The Gulf Stream off the Newfoundland Banks, where this tall iceberg was observed, is too superficial to float it, the warm current not being more than 100 fathoms deep, so that about three-quarters of its submerged volume is under the impact of the flow of glacial water f.'om the polar basin moving under and in a direction contrary to that of the Gulf Stream. Thus propelled by an invisible submarine force the berg in question had ploughed its southerly way against wind

and surfaee current to the forty-third parallel; and as the City of London reported it to be "in compaot form, which will take some months to disappear," it will no doubt advance much further south in the track of vessels moving between the Eastern ports of America and Europe, and possibly in the regular ship track from New York to Bio Janeiro, since the polar overflow which has it in tow trends far to the west of the Newfoundland meridians. It will be well, therefore, for vessels crossing tho West Atlantic basin, even on comparatively low latitudes, to be on their guard against this and timilar mammoth bergs.