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ECLIPSES.

book n.

cumstances as its corresponding eclipse in the preceding orfollowing period: but such is not the case. An eclipse ofthe Moon , which in the year 565 was of 6 digits 1 , was inthe year 583 of 7 digits, and in 601 of nearly 8. In 908the eclipse became total, and it remained so for about 12periods, or until the year 1088 : this eclipse continued todiminish until the commencement of the 15 th century, whenit totally disappeared in the year 1413. In a similarmanner, an eclipse of the Sun , which appeared at the North Pole in June, 1295, proceeded more southerly at eachperiod. On June 27, 1367, it made its first appearance inthe north of Europe ; in 1439, it was visible all over Europe ;at its 19th appearance in 1601, it was central in London ;on May 5, 1818, it was visible at London , and was againnearly central at that place on May 15, 1836. At its39th appearance, August 10, 1980, the Moon ’s shadowwill have passed the equator; and, as the eclipse will takeplace near midnight, will be invisible in Europe , Africa, andAsia . At every subsequent period the eclipse will go moreand more towards the south, until, finally, at its 78th ap-pearance on September 30, 2665, it will go off at the southpole of the Earth , and disappear altogether.

In the 18-year eclipse period, there usually happen 70eclipses, of which 41 are solar, and 29 are lunar. In anyone year the greatest number that can occur is 7, and theleast, 2 ; in the former case 5 of them may be solar, and 2lunar ; in the latter both must be solar. Under no circum-stances can there be more than 3 lunar eclipses in 1 year,and in some years there are none at all. Though eclipses ofthe Sun are more numerous than those of the Moon in theproportion of 41 to 29 (say 3 to 2), yet at any given placethere are more lunar eclipses visible than solar; because, whilst

1 A digit is the ^ part of the surface of the Sun or Moon ; and ofcourse an eclipse of 6 digits will he understood to he one in which 5 thedisc of the luminary is hidden. In the case of a lunar eclipse, whenthe magnitude is said to exceed 12 digits, it means that the Earth ’sshadow extends itself so many digits beyond the Moon ’s surface.