the
results had been telegraphed to the Atlantic seaboard, collected and
printed, and the papers were well out on their journey to European
readers."

The foregoing narrative will make amply clear the future possibilities
of telegraphy as a coadjutor of Astronomy in the observation of total
eclipses of the Sun. And if the will and the funds are forthcoming, the
eclipse of May 28, 1900, will afford an excellent opportunity of again
putting to the test the excellent ideas of which our American friends
worked out so successfully ten years ago. The zone of totality in that
eclipse passing as it will through so many of the densely populated
Southern States of North America, and then through Portugal, Spain, and
Algiers, great facilities will present themselves for telegraphic
combinations, if political and financial difficulties do not interfere.

FOOTNOTES:

[Footnote 111: There is a want of uniformity in Mrs. Todd's
references to times which I have not thought it necessary to put
straight. "Greenwich Mean Time," "Eastern U.S. Standard Time," and
"Pacific Time," are all severally quoted in happy-go-lucky
confusion.]

CHAPTER XV.

ECLIPSES OF THE MOON--GENERAL PRINCIPLES.

In dealing with eclipses generally, but with more especial reference to
eclipses of the Sun, in a previous chapter, it was unavoidable to mix
up in some degree eclipses of the Moon with those of the Sun. There
are, however, distinctions between the two phenomena which make it
convenient to separate them as much as possible. Eclipses of the Moon
are, like those of the Sun, divisible into "partial" and "total"
eclipses, but those words have a different application in regard to
eclipses of the Moon from what they have when eclipses of the Sun are in
question. A little thought will soon make it clear why this should be
the case. A partial eclipse of the Sun results from the visible body of
the Sun being in part concealed from us by the solid body of the Moon,
and so in a total eclipse there is total concealment of the one object
by the other.

But when we come to deal with partial and total eclipses of the Moon,
the situation, is materially different. The Moon becomes invisible by
passing into the dark shadow cast by the Earth into space.

[Illustration: FIG. 13.--THEORY OF AN ECLIPSE OF THE MOON.]

Fig. 13 will make this clear without the necessity of much verbal
explana