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accuracy accurately adjustment alidade altitude aneroid approximate artificial horizon azimuth barometer bearing celestial celestial equator centre chronometer circle clamp clinometer computed Corr correct COS1NES Cosine Parts Secant Diagram illustrating Diff difference of longitude E2ample equator Error of Watch Fahr fixed points geographical hour angle inches instrument intersection Length in feet lO-O log sine Logarithm magnetic mean measured meridian method Metres Feet micrometer Nautical Almanac object observations obtained occultation ordinary parallax parallel Parta plane table plane-table position prismatic compass probable error rays reading refraction Right Ascension S1NES screw Secant Cotang Secant Parts Cosine sextant shown sidereal sidereal day star station Statute Miles subtended subtract survey surveyor TABLE XXXVll.—(continued tacheometer taken Tangent Cosec Tangent Parts Cotang tangent-screw telescope temperature thermometer transit theodolite traveller traverse triangle vernier Versts vertical angles wires zero
Page 82 - In all four languages a noun referring to the distance from the end of the thumb to the end of the middle finger...
Page 84 - Sound at intervals from shore to shore, fixing your position on each occasion, by a sextant-angle between your starting-place and your assistant's station, and throw the floats overboard, signalling to your assistant when you do so, that he may note the interval that elapses before they severally arrive opposite to him. Take an angle from the opposite shore, to give the breadth of the river. To make the calculation approximately, protract the section of the river on a paper ruled to scale in square...
Page 74 - The logarithm of the quotient of two positive numbers is found by subtracting the logarithm of the divisor from the logarithm of the dividend. (6) The logarithm of a power of a positive number is found by multiplying the logarithm of the number by the exponent of the power. For, N" = (oT)
Page 68 - E from the top until within a short distance of the water, which it should never touch, and is supported in that position by an indiarubber washer F. The steam passes from the boiler up the tube E and escapes by the hole G.
Page 44 - To prove that the exterior angle of a triangle is equal to the sum of the two interior opposite angles (see fig.
Page 43 - The angle between the first and last directions of a ray which has suffered two reflections in one plane is equal to twice the inclination of the reflecting surfaces to each other. Let AB be the limb or graduated . arc, of a portion of a circle 60° in extent, but divided into 120 equal parts. On the radius CB let a silvered plane glass D be fixed, at right angles to the plane of the circle, and on the moveable radius CE let another such silvered glass, C, be fixed.
Page 25 - Also a large light box suffers much less from an accidental concussion than a small and heavy one. Thermometers travel best when slipped into india-rubber tubes. A coil of such tubing will serve as a floor, to protect a case of delicate instruments from the effects of a jar. Horse-hair is of use to replace old packing, but it has first to be prepared by steeping in boiling water, twisting into a rope, and, after it is firmly set, chopping it into short pieces. The hairs retain their curvature and...
Page 204 - For the same body the semidiameter varies with the distance; thus, the difference of the sun's semidiameter at different times of the year is due to the change of the earth's distance from the sun; and similarly for the moon and the planets.