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to the Sun , and in comparison with its immense distance, closeto one another. Then it may be understood that at the Moon will be moving onwards faster than the Earth , and will keep
in advance of it until, half-way between the time of Full andNew Moon , they occupy the relative positions m 2 and e 2 .After this, the Moon ’s speed will gradually fall more and moreshort of that of the Earth , and the Earth will gain upon ituntil, at the occurrence of New Moon , their places are m 3 ande 3 . The Earth next keeps in advance, although the Moon ’sspeed is gradually augmenting, until, after the lapse of anotherquarter of a lunation, they are to be found respectively at m 4and e 4 . Once more the Moon will gain upon the Earth untilat the next Full Moon their positions are m 5 and e„. Duringthe middle half of the month the Moon ’spath is seen to be farther away than theEarth ’s from the Sun ; during the othertwo quarters it lies within it.
A subsidiary diagram, Fig . XIII., drawnupon a larger scale, shows that an observerupon the Earth would at first see the Moon in the direction em^ presently in the direc- xm.-The apparenttiou EM, (corresponding to the places e 2 From the E^rth! 0 ™ 86011and m 2 in Fig . XII.), next in the direction em 3 , then iu the
Figures XII. and XIII. that the Me on has to describe this additionalportion of another revolution between being twice in succession Full orNew, in consequence of the onward motion of the Earth around theSun .