This entry contains remarks related to the following subject: Sea Ice

Published Journals of George W. DeLong

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I have hereinbefore mentioned that the greatest thickness of a single floe seen by us was 
seven feet ten inches, or say roughly eight feet. When, after ramming the ship through forty miles of 
leads last September, she was finally brought up, I pushed her into a crevice between two heavy 
floes which we subsequently found to be thirteen feet in thickness. I think this great depth was 
caused by the overriding of one floe on another, and regelation under pressure having taken place, 
the two became united as one mass. Mr. Dunbar, in his several tramps, has met ice which he 
describes as "so deep that you could now see how deep it was" This being rather vague, I directed 
him to-day to take with him a line, with hook attached, to catch under these floes, and thus give a 
measure of their thickness. Upon his return he reports that he measured floes ten and twelve feet 
thick, and some fourteen and fifteen feet thick, and the surface was "from a foot to eighteen inches 
above the water". It is, of course, impossible that such thicknesses should be ascribed to any one 
single floe. I am satisfied that when water has frozen to a thickness of eight feet the ice forms a 
blanket which effectually prevents the radiation of heat from the water beneath, and thus makes 
further freezing impossible. Any further thickness is due to deposits of snow on the surface, or the 
shoving under of another floe and a union by regelation between the two. When, last November, 
we were squeezed out of our icy bed and pushed out into water, we were as truly floating for a time 
as if in mid-ocean. The next day, however, we were iced in. This freezing continued from 
November 28th to January 17th, by which latter date the ice had a thickness of forty-eight inches 
(four feet). Subsequent measurements were rendered impossible by the smash up of the 19th of 
January, when floes so overrode and underrode our surrounding ice as to jumble it all in a heap. 
When we commenced to dig a canal around the ship we dug through four feet of ice before the 
water flowed in on us, but that depth was due to piling up, of course, and not to any direct freezing. 
As our leak has almost altogether subsided, it is safe to assume that we are buoyed up by a floe of 
ice extending down and under the keel, which floe, being lightened by its surface thawing under the 
ashes and refuse we had spread around us, is enabled to float so much higher. One of these days, 
let us hope, this mass will break and let us down to our bearings.

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Jeannette Ship's Journal

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