THE MOON.

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act upon it. But we have stated that the Moon has also avelocity of about 2,280 miles per hour from west to east roundthe Earth . As m is on the opposite side of the Earth to thatwhich it occupies with regard to the Sun , it is easy to see thatits rotation from west to east round the Earth will not carry itfrom m towards f, hut towards Q, in exactly the opposite direc-tion, through a distance of about 38 miles in a minute. Thecombined result is a motion equal to the difference of thesetwo, or of about 1062 miles in a 'minute towards f. Let thisdistance be mp. During this minute, however, the Earth ’sattraction would, as we have mentioned, bend the Moon ’s pathtowards itself ( i.e . in a direction approximately parallel to me),through a distance of about I 63 - feet. Let this be pr. Then rwill represent the position which the Moon would have at theend of a minute after leaving m, on the supposition that theSun ’s attraction were not acting upon it.

But the Sun would curve the path in the opposite direction,and with more than double power, so as to draw the Moon towards itself, through about 35 feet in the minute of whichwe are speaking. We therefore measure rn equal to 35 feet,and n will be very approximately the real place to which theMoon will attain.

The Earth will in the meantime have moved onwards, so as tobe still within its proper distance of about 240,000 miles fromthe Moon ; but this is not important as regards our presentexplanation. The essential point which is involved is this,that although in the diagram the lengths of rp and pn arenecessarily immensely exaggerated, and em and ms are drawnvery much shorter than they really are, the concavity of theMoon ’s path from m to n will clearly be turned towards the Sun .

And if this is the case when the Moon is New, the truth ofthe statement, which we may now make, that the Moon ’s pathis always concave to the Sun , may be easily realized. Forunder no other circumstances will the Earth tend to draw it sodirectly from the Sun as in the case we have just considered.At the time of Full Moon it will, in fact, draw it directlytowards the Sun, and make the concavity of its path towardsthat luminary so much the more pronounced. In other