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THE MOON .

thirteenth New Moon of that year, just before its close, may alsooccur sufficiently near to a passage of the line of Nodes throughthe Sun to produce an additional eclipse for the year inquestion. It results that in any given year ther q may be five,and there must be two, New Moons , which will produce totalsolar eclipses. If there be five, they may he the first andsecond, the seventh and eighth, and the thirteenth ; or thefirst, the sixth and seventh, and the twelfth and thirteenth.

One curious fact, little noticed in its connection with eclipsesin ordinary text-hooks, is, we think, deserving of special atten-

Fig . XXIII.—The Moon is nearer when seen in the zenith than when seen in the horizon.

tion. It is that the Moon really appears larger when over-head, or near to the zenith, than when seen in the horizon.On its rising there is no doubt that the first impressionafforded is just the reverse. But this is only an opticaldelusion, possibly caused by the mind to some extent fancyingits distance to he more comparable with that of terrestrialobjects which are also seen near to the horizon. But bytelescopic measurement, or even by looking through a tubedevoid of glasses, any one may easily arrive at the truth. Anda very elementary diagram may also suffice to show, that, ifthe Moon is at any time seen in the zenith of an observer,it is nearer to him than when seen in the horizon by a distance