The American Practical Navigator: Being an Epitome of Navigation and Nautical Astronomy

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U.S. Government Printing Office, 1888 - Nautical astronomy - 647 pages

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Page 635 - 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 636 - In like manner, when it is said, that " triangles on the same base, and between the same parallels, are equal...
Page 142 - Irish coast a lee shore; the ship was then kept close to the wind and several tacks made to preserve her position as nearly as possible until daylight, when, nothing being in sight, she was kept on ENE under short sail with heavy gales. At about 10 am an altitude of the Sun was observed and the chronometer time noted; but, having run so far without...
Page 627 - To find the logarithm of a vulgar fraction. RULE. Subtract the logarithm of the denominator from the logarithm of the numerator...
Page 632 - The circumference of a circle is supposed to be divided into 360 equal parts called degrees, and each degree into 60 equal parts called minutes, and each minute into 60 equal parts called seconds, &c.
Page 632 - A sphere is a solid bounded by a surface, every point of which is equally distant from a fixed point called the centre.
Page 632 - A plane rectilineal angle is the inclination of two straight lines to one another, which meet together, but are not in the same straight line.
Page 133 - Greenwich mean time, beginning at noon ; the dates are therefore astronomical. All the distances that can be observed on the same day are grouped together under that date ; and the columns are read from left to right, across both pages of the same opening. The letter W., or E., is affixed to the name of the sun, plauet, or star, to indicate that it is on the west, or east, side of the moon.
Page 626 - ... the difference between this logarithm and the next greater, and multiply it by the given number exclusive of the four first figures ; cross off at the right hand of the product as many figures as you had figures of the given number to multiply by ; then add the remaining left-hand figures of this product to the logarithm taken from the table, and to the sum prefix an index equal to one lese than the number of integral figures in the given number, and you will have the sought logarithm.
Page 142 - ... altitude must have happened at all the three points and at Small's light, and at the ship, at the same instant of time ; and it followed, that Small's light must bear ENE, if the Chronometer was right. Having been convinced of this truth, the ship was kept on her course. ENE, the wind being still SE, and in less than an hour, Small's light was made bearing ENE }^E., and close aboard.

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