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Common terms and phrases
angle angular distance astronomical axis azimuth bearing bright star called celestial concave celestial sphere centre chart chronometer circle co-ordinates compass constellation correction course curve declination deduced deviation diameter diff difference of latitude difference of longitude direction diurnal diurnal motion earth earth's surface east ecliptic equator equinoxes error fixed formulæ given Greenwich heavenly bodies heavens hemisphere hence horizon hour-angle inferior planets instrument interval length limb logarithm longitude lunar magnetic mean solar measured meridian meridian altitude method mile moon moon's motion Nautical Almanac nautical mile navigation needle noon object observed orbit parallax parallel sailing parallels of latitude passing plane sailing point of Aries polar distance position projection proper motion quadrantal reckoned refraction rhumb right ascension sextant ship ship's head sidereal spectator sphere spherical sun's term terrestrial tide tion triangle true vernier vers vertical wind
Popular passages
Page 97 - This disregard is neither supercilious nor causeless. The constellations seem to have been almost purposely named and delineated to cause as much confusion and inconvenience as possible. Innumerable snakes twine through long and contorted areas of the heavens, where no memory call follow them ; bears, lions, and fishes, large and small, northern and southern, confuse all nomenclature, &c.
Page 250 - ... sphere) the degrees of latitude remain the same, the degrees of longitude become less and less. In the chart, on Mercator's projection, the degrees of longitude are made everywhere of the same length, and, therefore, to preserve the proportion that exists at...
Page 399 - Snow, t „ Thunder. u .. Ugly threatening appearance in the weather. V „ Visibility of distant objects, whether the sky be cloudy or not. W „ Wet dew. „ Under any letter denotes an extraordinary degree. By the combination of these letters, all the ordinary phenomena of the weather may be recorded with certainty and brevity. EXAMPLES. bcm — Blue sky, with detached opening clouds, but hazy round the horizon. gv — Gloomy dark weather, but distant objects remarkably visible.
Page 210 - The longitude of a star is an arc of the ecliptic intercepted between the first point of aries and a secondary to the ecliptic passing through the star, measured according to the order of the signs.
Page 45 - Every year whose number is not divisible by 4 without a remainder, consists of 365 days ; every year which is so divisible, but is not divisible by 100, of 366; every year divisible by 100 but not by 400, again of 365; and every year divisible by 400, of 366.
Page 327 - ... intercepted between the first point of Aries and the circle of declination passing through the place of the body in the celestial concave.
Page iii - A Vade Mecum for practical Navigators of the Royal Navy, Mercantile Marine and Yacht Squadrons ; containing explanations of the technical terms used in Nautical Geography, Meteorology, and Astronomy ; hints to young officers for systematic study ; and information not generally accessible when wanted.
Page 317 - The sine of the angle of incidence bears to the sine of the angle of refraction a ratio, which is always the same for the same two media and is called the index of refraction.
Page 363 - Now, these two considerations are quite enough for our purpose, for they enable us to answer the question instantly and certainly by the following general rule : Look to the wind's eye — set its bearing by the compass — take the eighth point to the right thereof — and that will be the bearing of the centre of the storm in N.
Page 342 - The semidiameter of a heavenly body is half the angle subtended by the diameter of the visible disk at the eye of the observer. For the same body the semidiameter varies with the distance; thus, the difference of the...