Part 6 (1/2)

[Illustration: FIG 25--The Pleiades]

Without going thus far, and penetrating into telescopic depths, et some notion of these star-clusters with the help of a slasses, or even with the unaided eye, by looking at the beautiful group of the Pleiades, already fa it as a test of vision The littlethenitudes, which are in the following order:

Alcyone 30

Electra 45

Atlas 46

Maia 50

Merope 55

Taygeta 58

Pleione 63

Celaeno 65

Asterope 68

Good eyes distinguish the first six, sharp sight detects the three others

In the times of the ancient Greeks, seven were accounted of equal brilliancy, and the poets related that the seventh star had fled at the time of the Trojan War Ovid adds that she wasembraced by a God, as were her six sisters It is probable that only the best sight could then distinguish Pleione, as in our own day The angular distance froth of this republic, from Atlas and Pleione to Celaeno, is 4'/23”

of time, or 16' of arc; the breadth, from Merope to Asterope, is 36'[8]

In the quadrilateral, the length from Alcyone to Electra is 36', and the breadth froh, if the Full Moon were placed in front of this group of nine stars, she would cover it entirely, for to the naked eye she appears ether But this is not so She only measures 31', less than half the distance from Atlas to Celaeno; she is hardly broader than the distance froeta without touching either of these stars This is a perennial and very curious optical illusion When the Moon passes in front of the Pleiades, and occults them successively, it is hard to believe one's eyes The fact occurred, _eg_, on July 23, 1897, during a fine occultation observed at the author's laboratory of Juvisy (Fig 26)

[Illustration: FIG 26--Occultation of the Pleiades by the Moon]

Photography here discovers to us, not 6, 9, 12, 15, or 20 stars, but hundreds and millions

These are the arden

[Illustration: FIG 27--Stellar dial of the double star [galance at the them we are transported into immensities both of space and time, for the stellar periods measured by these distant universes often overpower in their nitude the rapid years in which our terrestrial days are estimated

For instance, one of the double stars we spoke of above, [gain, sees its two components, translucent diaravity, in one hundred and eighty years How le year of this star!--The Regency, Louis XV, Louis XVI, the Revolution, Napoleon, Louis XVIII, Louis Philippe, the Second Republic, Napoleon III, the Franco-Ger a single year of this radiant pair! (Fig 27)

But the pageant of the Heavens is too vast, too overwhel We must end our survey

Our Milky Way, with its millions of stars, represents for us only a portion of the Creation The illimitable abysses of Infinitude are peopled by other universes as vast, as i, as our ohich are renewed in all directions through the depths of space to endless distance Where is our little Earth? Where our Solar Systes, and return fro island

CHAPTER IV