The Method of Finding the Longitude at Sea, by Time-keepers: To which are Added, Tables of Equations to Equal Altitudes ...

C. Buckton, 1794 - Longitude - 115 pages

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Contents

 Section 1 1 Section 2 25 Section 3 29 Section 4 45 Section 5 90
 Section 6 96 Section 7 102 Section 8 Section 9 Section 10

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Page 16 - and the time correfponding to it will be the apparent time from the neareft noon: confequently, if the obfervation be made in the morning, the time thus found muft be taken from 24. hours, and the remainder will be the apparent time from the noon of the preceding day.
Page 16 - If the fun's declination and the colatitude of the ihip be one north and the other fouth, take their difference; but if they be both north, or both South, take their
Page 7 - As the earth revolves uniformly on its axis, if it had no annual motion in its orbit, or if that motion was uniform, and in a plane
Page 27 - a telefcope, of any convenient length, fixed at right angles to an horizontal axis; on which it turns in the plane of the meridian,
Page 16 - latitude, and the logarithmic fecant of the fun's declination ; their fum,' rejecting 20 from the index, muft be fought for in Table XVI. under log-rifing, and the time correfponding to it will be the
Page 19 - it will always Ihew the mean time at the firft meridian. Hence, if the mean time be found at the ihip, by the preceding problem, the difference between it and the time
Page 19 - will continue to ihew the mean time at that meridian, as long as it continues to go at the fame rate, whatever place it may be carried to : and,
Page 54 - attend again to the watch. And in this manner the times when the fun's firft limb arrives at every one of the wires muft be obferved, and noted down in its proper column. The times when the fécond limb arrives at each of the five wires muft be obferved in the fame manner, and written in
Page xiii - fhip is no otherwife an impediment in this fort of obfervations, than as it renders the repetition of them more
Page 4 - places exactly one hour after it commenced at Greenwich. In like manner, two hours after the time when it was noon at Greenwich, the