KNOTS
SIR,—The description of the " hand-log " given by Vice-Admiral Beamish is correct, but not his conclusion that therefore the knot is a unit of distance. Nicholls's Seamanship and Nautical Knowledge, which is the standard text-book for the Merchant Navy, describes the " hand log " and continues: " The principle in dividing off the log-line was to make the distance between the knots on the line bear the same proportion to a nautical mile (6,080 feet) as the seconds of the glass bore to the second? in an hour (3,600). . . . The common log is no longer used at sea and we have referred to it in the past tense, but reference to it is still of historical interest owing to the fact that the word knot,' which is a 'unit of speed' and not of distance, is derived from the marks on the hand log-line."
The Lords Commissioners of the Admiralty are equally definite. The Admiralty Manuat of Navigation states that "in navigation the unit of speed is the speed of one nautical mile per hour, and the unit is called the knot." Finally to confuse the issue I quote from an American hand- book, Reisenberg's Standard Seamanship for the Merchant Service: "Of course everyone knows that a knot is 6,080 feet and when we speak of a mile at sea we always mean a knot. The knot, mile, and minute of latitude (mean) are all the same, that is 6,o8o feet in length."—Yours faithfully, J. W. Boom. The Booth Steamship Company, Ltd., Cunard Building, Liverpool, 3.
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