## New American Practical NavigatorU.S. Government Printing Office, 1821 - Nautical astronomy |

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### Common terms and phrases

Aldebaran anchor angle apparent altitude arch azimuth bearing and distance brace cable calculated Cape central index centre co-sine column compass Corr correction corresponding course and distance course sailed degrees Diff difference of latitude difference of longitude Dist equal equator error EXAMPLE feet Funchal given Greenwich haul helm horizon glass instrument latitude and departure lee-way line of numbers logarithm mast means meridian altitude method middle latitude miles mizen moon moon's multiplied N.sine Nautical Almanac nearly noon object observed altitude parallax parallel Parallel Sailing passing the meridian perpendicular Plane Sailing points quadrant radius refraction right ascension rope rule sea account secant semi-diameter sextant ship ship's side sine star staysail subtracted sun's declination sun's right ascension Suppose tack taken tangent telescope topsails traverse table triangle true distance tude variation veer wind windward zenith distance

### Popular passages

Page xvi - In any triangle, the sum of the three angles is equal to two right angles, or 180°.

Page 102 - ... 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°...

Page 164 - To find the solidity of a pyramid and of a cone. RULE. — Multiply the area of the base by one third of its altitude, and the product will be its solidity.

Page 183 - The cause of the. tides is the unequal attraction of the sun and moon upon different parts of the earth. . For they attract the parts of the earth's surface nearest to them, with a greater force than they do its centre : and attract the centre more than they do the opposite surface. To restore this equilibrium the waters take a spheroidal figure, whose longer axis is directed towards the attracting luminary.

Page 22 - To find the logarithm of a vulgar fraction. RULE. Subtract the logarithm of the denominator from the logarithm of the numerator...

Page 186 - ... the miles the current sets per hour, and the bearing of the log will show the set of it. There is a very remarkable current, called the GULF STREAM, which sets in a north-east direction along the coast of America, * From Nathaniel Bowditch, THE NEW AMERICAN PRACTICAL NAVIGATOR, E.

Page 7 - TO THEIR DIFFERENCE ; So IS THE TANGENT OF HALF THE SUM OF THE OPPOSITE ANGLES', To THE TANGENT OF HALF THEIR DIFFERENCE.

Page 294 - In spherical triangles, whether right angled or oblique angled, the sines of the sides are proportional to the sines of the angles opposite to them.

Page 165 - If the vessel be double-decked, take the length thereof from the fore part of the main stem, to the after part of the stern post, above the upper deck ; the breadth thereof at the broadest part above the main wales...