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The practice of navigation and nautical astronomy. [With] Tables [and ...
Πλήρης προβολή - 1840
altitude alts angle appears apply azimuth bearing body called centre circle Coast compass Computation corr correction corresponding Cosec Cosine course Date decl declination determined diff difference direction Dist distance divided effect employed entr equal equator error extr feet figure given gives greater half head height Hence horizon hour-angle interval latitude less longitude mean measured meridian method miles minutes moon moon's nearly noon North object observation obtained parallel passes Places Lat Port position reduce result sailing seconds ship side sine South star subtract sun's Table taken Tangent term true variation watch West
Σελίδα 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.
Σελίδα 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...
Σελίδα 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.
Σελίδα 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.
Σελίδα 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...
Σελίδα 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.
Σελίδα 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.
Σελίδα 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.
Σελίδα 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.
Σελίδα 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...