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

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I think this book is wonderful with rich talents of a boy and the way he looks at things.

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added altitude angle apparent arch base bearing calculated called Cape central centre circle co-sine column compass correction corresponding course declination Degs departure Diff difference of latitude difference of longitude direct Dist distance divided division draw earth east equal equator error EXAMPLE extent feet figure fixed given gives glass greater half hand head Hence horizon Island length less light limb line of numbers logarithm Long lower manner marked means measured meridian method miles minutes moon moon's multiplied nearly noon object observation opposite parallax parallel passing perpendicular plane radius reach round rule sails scale Secant ship Shoal side sine square stand star subtracted sun's Suppose Table taken tangent telescope triangle true turn variation wind

### Popular passages

Page 2 - In any triangle, the sum of the three angles is equal to two right angles, or 180°.

Page 104 - ... 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 166 - 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 185 - 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 24 - 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 9 - TO THEIR DIFFERENCE ; So IS THE TANGENT OF HALF THE SUM OF THE OPPOSITE ANGLES', To THE TANGENT OF HALF THEIR DIFFERENCE.

Page 292 - 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 167 - 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...