Abstract
THAT Sir William Thomson's recent application of the pianoforte wire to sounding in small depths for the ordinary purposes of navigation is of great value, will be admitted readily by those who are familiar with the present process. But it occurs to me that a formidable objection to its general introduction into naval or mercantile vessels is to be found in the necessity of using chemically-prepared tubes for determining the depth of water. Sir William's latest device is (I believe) a straight glass tube two feet long, open at one end and inclosed ina brass tube attached above the sinker, in which air is compressed by the pressure of the water, the amount of compression being determined by the height to which the water rises in the tube. This height is marked by the decolorisation of a coating of chromate of silver on the inside of the tube, effected by the sea-water. A number of such tubes, properly prepared, must therefore be kept at hand, and when once used they must be coated anew, an operation of no little difficulty.
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JEWELL, T. Sounding Apparatus . Nature 17, 230 (1878). https://doi.org/10.1038/017230a0
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DOI: https://doi.org/10.1038/017230a0