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There is no apparent flattening of the lunar orb asseen from the earth; the most careful measurementpresents it as circular. Since the earth’s semi-diameter subtends from the moon an angle or arc of57' 2" - 7, or 3,422"'7, while the moon’s diameter sub-tends from the earth an angle of l,865"’l, it followsthat the moon’s diameter is less than the earth’sradius (or 3,962 - 9 miles) in the proportion of 18,651to 34,227. Thus it is readily calculated (by mererule of three) that the moon’s real diameter (or atleast any diameter square to the line of sight fromthe earth) is 2,159 - 6 miles. It chances that this isthe exact value adopted by Mildler, though obtainedby employing a different value of the lunar parallax,of the lunar apparent diameter, and lastly of theearth’s real diameter.
It follows that the earth’s equatorial diameter exceedsthe moon’s in the proportion of about 3,670 to 1,000;or, if we represent the earth’s equatorial diameter by10,000, then the moon’s would be represented by2,725. Assuming the moon’s shape to be globular,and the earth’s compression —, it follows that theearth’s surface exceeds the moon’s in the proportionof about 13,435 to 1,000; or, if we represent theearth’s surface by 10,000, the moon’s will be repre-sented by 744. Lastly, on the same assumption as tothe moon’s shape, the earth’s volume exceeds themoon’s in the proportion of about 49,263 to 1,000;or, if the earth’s volume be represented by 10,000,the moon’s will be represented by 209.