The first piece of this cord is termed the "stray line," and is generally of the same length as the ship, so as to allow for the eddy and wash of the wake astern; and, at the end of this stray line, a piece of bunting is inserted in the coil, from which a length of forty-seven feet three inches is measured off and a disc of leather put on the line to mark the termination of the first knot, or nautical mile. Two knots are put at the end of another length of forty-seven feet three inches; three knots at a third, and so on, until as much of the line has been thus measured and marked off at equal distances as will test the utmost sailing capacity of the ship--a single knot being placed midway, also, between each of these divisions, to denote the half knots. Two sand-glasses are used in connection with the log-line, as the old quartermaster, who was our instructor in this branch of our nautical education, explained, the one called "the long glass," which runs out in twenty-eight seconds, while the other is a fourteen-second glass, which is generally adopted at sea when the ship is going over five knots with a fair wind. The first mentioned is only used in light breezes; and, as Bob Ricketts showed us by careful manipulation, reeling off bights of the line and keeping the slack loosely in his hands, the thing to be particular about is to heave the log-ship over the side clear of the ship, and see the glass turned as soon as the bunting mark is reached, denoting that all the "waste" has run out. Then, whatever mark you can distinguish on the line nearest to your hand at the expiration of the allotted twenty-eight or fourteen seconds, when the man holding the glass sings out "Stop!" as the last grain of sand empties itself out of the bulb, that will be the speed of the ship. The division of knots on the log-line bear the same proportion to a mile, as the twenty-eight or fourteen seconds of the glass does to an hour of time; so, if the four-knot mark be to hand, and the "long" glass be used, she is going four knots, or nautical miles, per hour. It will be eight knots if the "short glass" be the standard of measurement; the time the line has taken being only half the former, and the number of the knots having to be doubled to keep the proportion between the length of line and the space of time equal. It did not take me long to master what the old quartermaster had to teach me on this point; but some of the other cadets were awfully stupid at first, I must say, particularly that brute Andrews, in spite of his bumptiousness and conceit. He gave old Ricketts a lot of trouble before he remembered to put in the pin prior to pitching the log-ship overboard; though without this it could not float upright, and was as good as useless to gauge our speed. The ass could not be made to understand this, and omitted putting in the pin time after time so persistently, that Ricketts had to tell the commander that he "could make nothing out of him."