The story of eclipses simply told for general readers (1909)

Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: 1899.June8. 23.O.'. JuneApproximate Mid-interval.IS- Junec. Dec. Dec.a. 16.O.' ' ' JDec.9- c. 1900.May June28. 13-0 .'. '. '. fJune5- Nov.29.o .. . . Nov.22.1901.May May3-c.' MayIO. 1 8.0. Oct.7-C)- Nov.3- Nov.zi.© . 1902.April8.o .' ' ' ) April22.I. - April22.4HI May7-0 .. . . ) Oct. Oct.17- 31.C. 0 ." ' ' j-Oct.24.The Epochs in the last column which are marked with stars () or () as the case may be, represent corresponding nodes so that from any one single-star date to the next nearest single-star date means an interval of one year less (on an average) the 19$ days spoken of on p. 29 (ante). A glance at each successive pair of dates will quickly disclose the periodical retrogradation of the eclipse epochs. CHAPTER IV. MISCELLANEOUS THEORETICAL MATTERS CONNECTED WITH ECLIPSES OF THE SUN (CHIEFLY). One or two miscellaneous matters respecting eclipses of the Sun (chiefly) will be dealt with in this chapter. It is not easy to explain or define in words the circumstances which control the duration of a Solar eclipse, whereas inthe case of a lunar eclipse the obscuration is the same in degree at all parts of the Earth where the Moon is visible. In the case of a Solar eclipse it may be total, perhaps, in Africa, may be of six digits only in Spain, and of two only in England. Under the most favourable circumstances the breadth of the track of totality across the Earth cannot be more than 170 miles, and it may be anything less than that down to zero where the eclipse will cease to be total at all, and will become annular. The question whether a given eclipse shall exhibit itself on its central line as a total or an annular one depends, as has been already explained, on the varying distances of the Earth and the Moon from the Sun in different parts of their respective...