Lessons in astronomy including uranography. A brief intoductory course without mathematics (1896)
Young, Charles A. (Charles Augustus), 1834-1908 · Boston, London, Ginn and company · leaf 86
owledge in our readers, that the earth is orange-shaped, oran oblate spheroid, the diameter from pole to pole being7899.74 miles, while the equatorial diameter is 7926.61 miles.The difference, 26.87 miles, is about -^-^ of the equatorialdiameter. This fraction, -j^, is called the oblateness or… … itude are longest at the pole. It is because the earths surface there ismore nearly flat than anywhere else, so that a person has to travelmore miles to change thedirection of his plumb- a\ ^P \b line one degree. Fig. 11illustrates this. The an-gles adb and fhg are equal,but the arc ab is…
Astronomy
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