"...a lunar eclipse arises from... a body semi-transparent and well-defined passing before the moon; or between the moon's surface and the observer on the surface of the earth.
That many such bodies exist in the firmament is almost a matter of certainty; and that one such as that which
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eclipses the moon exists at no great distance above the earth's surface, is a matter admitted by many of the leading astronomers of the day. In the report of the council of the Royal Astronomical Society, for June 1850, it is said:--
"We may well doubt whether that body which we call the moon is the only satellite of the earth."
In the report of the Academy of Sciences for October 12th, 1846, and again for August, 1847, the director of one of the French observatories gives a number of observations and calculations which have led him to conclude that,--
"There is at least one non-luminous body of considerable magnitude which is attached as a satellite to this earth."
Sir John Herschel admits that:--
"Invisible moons exist in the firmament." 1
Sir John Lubbock is of the same opinion, and gives rules and formulæ for calculating their distances, periods, &c. 2
At the meeting of the British Association for the Advancement of Science, in 1850, the president stated that,---
"The opinion was gaining ground, that many of the fixed stars were accompanied by companions emitting no light."
"The 'changeable stars' which disappear for a time, or are eclipsed, have been supposed to have very large opaque bodies revolving about or near to them, so as to obscure them when they come in conjunction with us." 3
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"Bessel, the greatest astronomer of our time, in a letter to myself, in July 1844, said, 'I do indeed continue in the belief that Procyon and Sirius are both true double stars, each consisting of one visible, and one invisible star.' . . A laborious inquiry just completed by Peters at Königsberg; and a similar one by Schubert, the calculator employed on the North American Nautical Almanack, support Bessel." 1
"The belief in the existence of non-luminous stars was prevalent in Grecian antiquity, and especially in the early times of Christianity. It was assumed that 'among the fiery stars which are nourished by vapours, there move other earthy bodies, which remain invisible to us!' Origenes." 2
"Stars that are invisible and consequently have no name move in space together with those that are visible." Diogenes of Appollonica. 3
Lambert in his cosmological letters admits the existence of "dark cosmical bodies of great size." 4
We have now seen that the existence of dark bodies revolving about the luminous objects in the firmament has been admitted by practical observers from the earliest ages; and that in our own day such a mass of evidence has accuмulated on the subject, that astronomers are compelled to admit that not only dark bodies which occasionally obscure the luminous stars when in conjunction, but that cosmical bodies of large size exist, and that "one at least is attached as a satellite to this earth." It is this dark or "non-luminous satellite," which when in conjunction,
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or in a line with the moon and an observer on earth, IS THE IMMEDIATE CAUSE OF A LUNAR ECLIPSE."
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