The New American Practical Navigator: Being an Epitome of Navigation; Containing All the Tables Necessary to be Used with the Nautical Almanac, in Determining the Latitude, and the Longitude by Lunar Observations ... : With an Appendix Containing Methods of Calculating Eclipses of the Sun and Moon ...Edmund M. Blunt, Proprietor and author of the American coast pilot ; John Gray & Company, Print., 1826 - Nautical astronomy - 617 pages |
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Page 4
... CENTRE , and the line described by the other point is called the CIRCUMFERENCE . VI . The RADIUS of à circle , or SEMIDIAMETER , is a right line drawn from the centre to the cir- cumference , as AC ; or it is that line which is taken ...
... CENTRE , and the line described by the other point is called the CIRCUMFERENCE . VI . The RADIUS of à circle , or SEMIDIAMETER , is a right line drawn from the centre to the cir- cumference , as AC ; or it is that line which is taken ...
Page 5
... centre of the circle being the angular point . Thus the angle A is measured by the arch BC describ- ed round the point A as a centre , and the angle is said to be of as many degrees as the arch is , that is , if the arch BC is 30 ...
... centre of the circle being the angular point . Thus the angle A is measured by the arch BC describ- ed round the point A as a centre , and the angle is said to be of as many degrees as the arch is , that is , if the arch BC is 30 ...
Page 6
... centre through the other end of the arch ; thus AT is the tangent of the arch AS . XXIII . The Co - TANGENT of an arch is the tangent of the complement of that arch to a quadrant ; thus HG is the tangent of the arch HS or the co - tan ...
... centre through the other end of the arch ; thus AT is the tangent of the arch AS . XXIII . The Co - TANGENT of an arch is the tangent of the complement of that arch to a quadrant ; thus HG is the tangent of the arch HS or the co - tan ...
Page 7
... centre , describe the cir- cular arch CAD , cutting the line CD in C and D ; then ( by art . 6 ) this arch is equal to a semicircle , but it is also equal to the sum of the arches CA and AD , the measures of the two angles ABC , ABD ...
... centre , describe the cir- cular arch CAD , cutting the line CD in C and D ; then ( by art . 6 ) this arch is equal to a semicircle , but it is also equal to the sum of the arches CA and AD , the measures of the two angles ABC , ABD ...
Page 9
... centre standing upon the same arch . Thus , the angle BAD is half the angle BCD standing upon the same arch BD of the circle BEDA , whose cen- tre is C. To demonstrate this , draw through A and the centre C the right line ACE , then ...
... centre standing upon the same arch . Thus , the angle BAD is half the angle BCD standing upon the same arch BD of the circle BEDA , whose cen- tre is C. To demonstrate this , draw through A and the centre C the right line ACE , then ...
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Common terms and phrases
anchor angular distance apparent altitude arch azimuth bearing calculation central index centre chronometer circle co-sec co-sine column compass corresponding course sailed degrees diameter Diff difference of latitude difference of longitude Dist divided draw elapsed equal equator error EXAMPLE feet Funchal given gives Greenwich half sum horizon glass hour angle hypotenuse instrument latitude and departure line of numbers logarithm mean meridian altitude method middle latitude miles minutes moon moon's multiplied Nautical Almanac nearly noon object observed altitude obtained parallax parallel passing the meridian perpendicular Plane Sailing points poles quadrant radius 90 refraction right ascension rule sea account secant semi-diameter sextant ship ship's side sine square star subtracted sun's declination sun's lower limb Suppose taken tangent telescope tion TRAVERSE TABLE triangle true altitude true distance tude variation watch wind zenith distance
Popular passages
Page 10 - 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 5 - In a right triangle, the side opposite the right angle is called the hypotenuse, and the other two sides the legs.
Page 187 - 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...
Page 28 - To find the logarithm of a vulgar fraction. RULE. Subtract the logarithm of the denominator from the logarithm of the numerator...
Page 240 - Sear up, or bear away, is to change the course of a ship, in order to make her run before the wind...
Page 13 - TO THEIR DIFFERENCE ; So IS THE TANGENT OF HALF THE SUM OF THE OPPOSITE ANGLES', To THE TANGENT OF HALF THEIR DIFFERENCE.
Page 205 - 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 187 - ... take the depth from the under side of the deck plank to the ceiling in the hold, then multiply and divide as aforesaid, and the quotient shall be deemed the tonnage.
Page 6 - CO-SINE of an arch is the sine of the complement of that arch, or of what that arch wants of a quadrant ; thus AH being a quadrant, the arch SH is the complement of the arch AS ; SZ is the sine of the arch SH, or the co-sine of the arch AS. XXI. The VERSED SINE of an arch is that part of the diameter...
Page 91 - The index and horizon glasses must be perpendicular to the plane of the instrument, and their planes parallel to each other, when the index division of the vernier is at 0° on the arc ; and the optical axis of the telescope must be parallel to the plane of the instrument. We shall speak separately of each of these adjustments.