Sidereal System called the Milky Way. 83 
CEnopidas of Chios also asserted that he had learnt from the 
Egyptian priests that the sun moved in the Milky Way, and 
then, mistaking his apparent annual motion for his real mo- 
tion, added with poetic fiction, that the sun, horror-struck at 
the sight of the banquet of Thyestes, turned from his course, 
and revolved ever afterwards in the ecliptic *. The essence 
and the structure of this part of the heavens remained uncer- 
tain up to the present time : to this the great poet of the Divina 
Commedia alluded when he said,— 
* Come distinta da minori e maggi 
Lumi biancheggia fra i poli del mondo 
Galassia si che fa dubbiar ben saggi.”” 
Parad. canto xiv. ver. 97. 
** As leads the galaxy from pole to pole, 
Distinguish’ into greater lights and less, 
Its pathway which the wisest fail to spell.” 
Cary’s Translation, verse 90. 
It was the celebrated astronomer Sir W. Herschel who, 
penetrating it with his powerful telescopes, analysed its for- 
mation. He saw the light, which was concentrated in distinct 
points, present the appearance of an immense number of stars, 
so that he was able to conclude that more than 50,000 stars 
had passed over the field of his telescope in a zone only two 
degrees in breadth during the short space of one hour. Thus 
was completely verified the conjecture, already put forth by 
Democritus, that that light was in the greatest part the effect 
of the concourse of a multitude of stars too minute or too re- 
mote to be distinctly perceived. 
The more Herschel was aided by his instruments, which were 
wrought to so high a degree of perfection by his genius, the 
more acute he showed himself in drawing his conclusions. He 
supposed then that the Milky Way was a cluster of stars, a re- 
solvable nebula in the form of a stratum, of which the thick- 
ness, although immense, was yet very small in comparison with 
its other dimensions, and in which the sun and his system of 
planets were placed. As any person who stands in the midst 
of a low stratum of thin and transparent haze perceives it above 
and close to him, while it appears thicker and darker in the 
distance, until it assumes the form of a circle of greyish light 
along the horizon, so an observer who is placed in the milky 
nebula must see the stars thinly scattered if he looks around 
him ; whereas if he directs his visual ray along the plane of the 
stratum he will see them thickly condensed: and if with his 
eye directed along that plane he sweeps from one end of the sky 
"4 Vide cap. xxiv. of the Introduction to the Phenomena of Aratus, 
written by Achilles Tatius, and inserted inthe Uranologium of Pere Piteau, 
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