The practice of navigation and nautical astronomy. [With] Tables [and] Supplement to the first ed, Volume 261870 |
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Page vi
... employed , and , in general , two only ; namely , an approximate method , and a complete , or , as it is called , rigorous , method . The former may often serve in cases of haste , or when precision is not necessary , and will also ...
... employed , and , in general , two only ; namely , an approximate method , and a complete , or , as it is called , rigorous , method . The former may often serve in cases of haste , or when precision is not necessary , and will also ...
Page vii
... employed by that distinguished navigator . The remaining observations have been furnished to me by the Rev. G. Fisher , astronomer to Sir Edward Parry's expedition to the Polar Seas . In order to enable the computer to judge of the ...
... employed by that distinguished navigator . The remaining observations have been furnished to me by the Rev. G. Fisher , astronomer to Sir Edward Parry's expedition to the Polar Seas . In order to enable the computer to judge of the ...
Page viii
... employed , because a single result in which six places are necessary cannot be depended upon to the degree of precision obtained . On the same principle , some of the logarithms are given to three places only . The log . sine square of ...
... employed , because a single result in which six places are necessary cannot be depended upon to the degree of precision obtained . On the same principle , some of the logarithms are given to three places only . The log . sine square of ...
Page ix
... Employed merely as a check , a single chronometer cannot fail to prove of great service ; but too firm a reliance on such an instrument would lead to the dangerous error of relaxing that vigilance which the known uncertainty of the ...
... Employed merely as a check , a single chronometer cannot fail to prove of great service ; but too firm a reliance on such an instrument would lead to the dangerous error of relaxing that vigilance which the known uncertainty of the ...
Page xi
... employed . The present volume being thus , in the ordinary practice of navigation , independent of the second , no notice of another volume appears in the title - page . By the term Theory is commonly understood , in this particular ...
... employed . The present volume being thus , in the ordinary practice of navigation , independent of the second , no notice of another volume appears in the title - page . By the term Theory is commonly understood , in this particular ...
Other editions - View all
The Practice Of Navigation And Nautical Astronomy. [with] Tables [and ... Henry Raper No preview available - 2019 |
The Practice Of Navigation And Nautical Astronomy. [with] Tables [and ... Henry Raper No preview available - 2022 |
Common terms and phrases
add the log altitude alts appears Azim azimuth bearing called centre chronometer circle compass Computation corr correction cosec Course and Distance D.Lat Dist decimal decl declination degree deviation diff difference direction divided employed equal equator error feet find the Course fraction given gives greater Greenwich Date height of eye Hence horizon hour-angle interval latitude less logarithms longitude magnetic magnetic bearing mean measured meridian method miles moon moon's multiplied Nautical Almanac nearly noon observation parallax parallel Parallel Sailing Plane Sailing planet pole prime vertical prop proportion quantity radius ratio reckoned reduce refraction result rhumb line right angles Right Ascension sailing Semid sextant shews ship ship's head side sine star subtract sum rejecting tens sun's TRAVERSE TABLE triangle true true alt variation watch
Popular passages
Page 41 - The angle in a semicircle is a right angle ; the angle in a segment greater than a semicircle is less than a right angle; and the angle in a segment less than a semicircle is greater than a right angle.
Page 147 - Since the apparent altitude is too great on account of refraction, and too small on account of parallax, the diff. between these quantities is the diff. between the true and apparent altitudes. This difference, or the combined effect of parallax and refraction, is called the Correction of Altitude. The moon's Corr. of Alt. is given in Table 39; that of a star is merely its refraction. 439. The SEMI-DIAMETER of a celestial body is half the angle subtended by the diameter of the visible disc. Thus...
Page 38 - A parallelogram is a four.sided figure, of which the opposite sides are parallel; and the diameter is the straight line joining two of its opposite angles.
Page 19 - The characteristic of a number less than 1 is found by subtracting from 9 the number of ciphers between the decimal point and the first significant digit, and writing — 10 after the result.
Page 43 - ... section shall be parallel to the remaining side of the triangle. Let DE be drawn parallel to BC, one of the sides of the triangle ABC: then BD shall be to DA, as CE to EA. Join BE, CD; then the triangle BDE is equal...
Page 105 - The distance between two points on the surface of a sphere is the length of the minor arc of a great circle between them.
Page 186 - A line drawn from Polaris perpendicular to the line of the Pointers, and on the opposite side to the Great Bear, passes, at 48° distance, through CAPELLA, one of the brightest stars. In this same line, about the same distance on the opposite side of the pole, is a.
Page 145 - ... of Altitude are circles parallel to the horizon. 431. ZENITH DISTANCE is the arc included between the zenith and the celestial body, or the angular distance of a body from the zenith of which that arc is the measure. The zenith distance is, therefore, the complement of the altitude to 90°, as Z A.
Page 4 - RULE. Multiply all the numerators together for a new numerator, and all the denominators for a new denominator: then reduce the new fraction to its lowest terms.
Page 358 - Frigate La Venus, 1836-9, vol. iii. p. 419) paid particular attention to this indication, and remarks that the observations generally shew a lowering of the thermometer on approaching land, but they disprove that the water on a bank is always colder.* 1039. The temperature of the sea has been observed to change several degrees, in intervals of time varying from a few hours to a day and a half previous to a change of wind, the water becoming gradually warmer when the wind was about to blow from a...