The Method of Finding the Longitude at Sea: By Time-keepers: to which are Added, Tables of Equations to Equal Altitudes. More Extensive and Accurate Than Any Hitherto Published. By William Wales, ... |
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The Method of Finding the Longitude at Sea, by Time-Keepers: To Which Are ... William Wales No preview available - 2018 |
The Method of Finding the Longitude at Sea by Time-Keepers: To Which Are ... William Wales No preview available - 2015 |
Common terms and phrases
০,০০০,০০০,০০ 24 hours alſo altered its rate altitude Appa apparent noon aſſiſtant axis Barbadoes becauſe beſt cauſe conſequently Correction decreaſes deviation diffe diſtance eaſt elapſed elevated pole equa equation equinoctial exactly fame faſt finding the rate firſt limb firſt meridian fixed ſtar flow for mean folar Fomalhaut fome fouth fubtracted fun's declination fun's longitude gain glaſs half half-interval horizon increaſes inſtant inſtrument interval laſt latitude leſs logarithm longitude for noon loſes minutes muſt Nautical Almanac neceſſary noon at Greenwich number of days O's Long obſerved difference oppoſite parallax paſs paſſed perſons purpoſe rate of going repreſented reſpect reſt right aſcenſion ſame ſcrew g ſecant ſecond ſervation ſerved ſet ſextant ſhall ſhew ſhewn ſhip ſigns ſmall ſome ſpace ſtar's ſtill ſubject ſuch ſum ſun's ſuppoſe Table Take the difference tangent teleſcope theſe thoſe time-keeper tion tranfit true altitude tude uſe watch goes weſt
Popular passages
Page 18 - 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 18 - 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 9 - 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 29 - 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 18 - 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 21 - 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 21 - 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 56 - 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 xv - fhip is no otherwife an impediment in this fort of obfervations, than as it renders the repetition of them more
Page 6 - places exactly one hour after it commenced at Greenwich. In like manner, two hours after the time when it was noon at Greenwich, the