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adjusted angle apply axis base line bearing called centre column compass correction corresponding Cosine Cotang course decimal departure describe determined difference difference of level direction distance divided draw drawn east equal error example extremity feet field figure give given greater ground half hence horizontal horizontal plane inches intersection known land latitude length less limb logarithm longitude manner marked means measure meridian method middle miles notes object observed parallel passing perpendicular piece plate plot position radius reading REMARK represent right angles rods sailing scale screws ship side sights Sine square staff stakes station subtract suppose surface survey taken Tang telescope theodolite triangle true turn variation vernier vertical yards
Page 12 - The logarithm of . the quotient of two numbers, is equal to the logarithm of the dividend diminished by the logarithm of the divisor.
Page 47 - C' (89) (90) (91) (92) (93) 112. In any plane triangle, the sum of any two sides is to their difference as the tangent of half the sum of the opposite angles is to the tangent of half their difference.
Page 140 - ... the time of revolution is 23 h. and 56 min. To the eye of an observer, this star is continually in motion, 'and is due north but twice in 23 h. 56 min. ; and is then said to be on the meridian. Now, when it departs from the meridian, it apparently moves east or west, for 5 h. and 59 min., and then returns to the meridian again. When at its greatest distance from the meridian, east or west, it is said to be at its greatest eastern or western elongation.
Page 63 - Being on a horizontal plane, and wanting to ascertain the height of a tower, standing on the top of an inaccessible hill, there were measured, the angle of elevation of the top of the hill 40°, and of the top of the tower 51° ; then measuring in a direct line 180 feet farther from the hill, the angle of elevation of the top of the tower Cway 33° 45' ; required the height of the tower.
Page 11 - THE LOGARITHM: of a number is the exponent of the power to which it is necessary to raise a fixed number, to produce the given number.
Page 144 - Now, if the elongation, at the time of observation, was west, and the north end of the needle is on the west side of the line, the azimuth, plus the angle shown by the needle, is the true variation. But should the north end of the needle be found on the east side of the line, the elongation being west, the difference between the azimuth and the angle would show the variation, and the reverse when the elongation is east. 1. Elongation west, azimuth 2° 04' North end of the needle on the west, angle...
Page 41 - The secant of an arc is the line drawn from the centre of the circle through one extremity of the arc, and limited by the tangent passing through the other extremity. Thus, 00 is the secant of the arc AB.
Page 46 - CB : CA : : sin A : sin B. For, with A as a centre, and AD equal to the less side...