ICE AND ICEBERGS.
During the Austro-Hungarian Arctic Expedition of the years 1872-1874, a number of interesting experiments were made on ice phenonema. For example, on the sth March, a cube of ice was sunk under the icefield to the depth of five metres. After a lapse of twenty-four hours it was found that a crust of new ice had formed itself over it about one em. thick. This was caused by the low temperature of the block itself, and, from a similar cause, ice crystals had formed between the edges of the hole, owing to the coldness of the walls. On the 10th March very little increase in the added layer of ice on the cube was to be observed. On the 20th March this newly-formed ice was found to be softened so that it was easily impressed by the finger ; by the 2nd April it had become harder again, though porous and apparently a little increased. From thence onward the block dwindled regularly, especially on that part of its surface which was turned upwards ; on the 19th July it was only a third of its original size; nevertheless the hole through which it was sunk had, during the last period, become entirely closed by young, ice at its lower margin. This experiment shows the loss of ice from below by the action of the warmth of the water. The author concludes from his experiments and measurements that compact salt-water ice can never obtain a greater thickness than 10 metres. Icebergs are subjected to disintegration after somewhat the same manner as rocks commonly are. They are full of crevices, into which the water formed by melting penetrates ; in winter this water freezes, and by its expansion all through the glacier a rupture of the mass ensues. “It is highly probable that most of the icebeigs afloat in winter are in such a condition that a very slight cause is sufiicient to make them burst because of the state of internal tension. Every polar teaveller can tell how a shot, the driving in of an ice anchor, or any other sudden vibration, has brought about the catastrophe ; cases have even occurred in which the sound of the voice alone was sufficient. An iceberg is always an unpleasant neighbor.” So many are the causes which tend to destroy icebergs that the author conludes ‘ ‘ no berg exists which could withstand them more than ten years, and that commonly the life of a berg is much shorter.” However this may be, doubtless the much larger Antartic bergs last very much longer, as must necessarily occur because of the much greater uniformity of the climate to which they are export.
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ICE AND ICEBERGS., Ashburton Guardian, Volume 1, Issue 78, 25 March 1880
ICE AND ICEBERGS. Ashburton Guardian, Volume 1, Issue 78, 25 March 1880
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