The seaman's new daily assistant, exhibiting an easy and expeditious method of keeping a ship's reckoning at sea (Google eBook)

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Page 106 - LV. contains the times of high water on the full and change of the moon, with the vertical rise of the tide, at many ports, harbors.
Page 31 - Then, if the zenith distance and declination be both north or both south, add them together; but if one be north and the other south, subtract the less from the greater, and the sum or difference will be the latitude, of the same name with the greater.* EXAMPLE I.
Page 34 - ... or taking their difference when of contrary names : the altitude to be reckoned from the South point of the horizon, when the latitude is North, and the contrary when South ; but when the sum exceeds 90°, it is to be taken from 180°, and reckoned from the opposite point of the horizon, that is, from the North in North latitude, and from the South in South latitude.
Page 35 - The true amplitude of any celestial object is an arch of the horizon contained between the true east or west points thereof and the centre of the object at the time of its rising or setting ; or it is the degrees and...
Page 2 - When the latitudes are both of the same name, that is, both North or both South, subtract the less from the greater, and the remainder will be the difference of latitude.
Page 23 - Take the distance between the ship and given place in your compasses and apply it to the side of the chart or graduated meridian, setting one foot as much above one place as the other is below the other place, the number of degrees between the points of the compasses will be the distance nearly. When the places bear north and south of each other this rule is accurate ; but when they bear nearly east and west, and the distance is large, it will err considerably ; but in general it is exact enough...
Page 11 - II. the difference of latitude and departure corresponding to each course and distance, and set them in their respective columns : then the difference between the sums of the northings and southings will be the difference of latitude made good, of the same name with the greater ; and the difference between the sums of the eastings and westings will be the departure made good, of the same name with the greater quantity.
Page viii - If the latitudes or longitudes are both in the same direction,!, e. both east or both west, both north or both south, subtract the les,s from the greater, and the remainder will be the différence.
Page 25 - Centigrade is equal to j of Reaumur. Multiply the given number of degrees of the Centigrade by 4, and divide the product by 5 ; the quotient will be the equivalent number of degrees on Reaumur's scale.
Page 38 - ... making proper allowance for the variation. At the time of leaving the land, the bearing of some point or place is to be carefully observed, whose latitude and longitude are known ; which, together with the estimated distance of the ship from such point or place, is to be noted down on the log-board. This is called taking a departure. As the distance inferred from estimation is very susceptible of error, particularly in hazy weather, or when that distance is considerable, it will be advisable...

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