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566
THE POPULAR SCIENCE MONTHLY.

what seemed a star is, in reality, a mass of small stars intermixed with a diffused nebulosity.

It is very remarkable circumstance that Galileo, whose small telescope, directed to the clear skies of Italy, revealed so many interesting phenomena, failed to detect

"That marvellous round of milky light
Below Orion."

It would not, indeed, have been very remarkable if he had simply failed to notice this object. But he would seem to have directed his attention for some time especially to the region in the midst of which Orion's nebula is found. He says: "At first I meant to delineate the whole of this constellation; but, on account of the immense multitude of stars—being also hampered through want of leisure—I left the completion of this design till I should have another opportunity." He therefore directed his attention wholly to a space of about ten square degrees, between the belt and sword, in which space he counted no less than 400 stars. What is yet more remarkable, he mentions the fact that there are many small spots on the heavens shining with a light resembling that of the Milky-Way (complures similis coloris areolœ sparsim per cethera subfulgeant); and he even speaks of nebulae of this sort in the head, and belt, and sword of Orion. He asserts, however, that, by means of his telescope, these nebulae were distinctly resolved into stars—a circumstance which, as we shall see presently, renders his description wholly inapplicable to the great nebula. Yet the very star around which (in the naked-eye view) this nebula appears to cling, is figured in Galileo's drawing of the belt and sword of Orion!

It seems almost inconceivable that Galileo should have overlooked the nebula, assuming its appearance in his day to have resembled that which it has at present. And, as it appears to have been established that, if the nebula has changed at all during the past century, it has changed very slowly indeed, one can scarcely believe that in Galileo's time it should have presented a very different aspect. Is it possible that the view suggested by Humboldt is correct—that Galileo did not see the nebula because he did not wish to see it? "Galileo," says Humboldt, "was disinclined to admit or assume the existence of starless nebulae." Long after the discovery of the great nebula in Andromeda—known as the "transcendently-beautiful queen of the nebulæ"—Galileo omitted all mention in his works of any but starry nebulae. The last-named nebula was discovered in 1614 by Simon Marius, whose claims to the discovery of Jupiter's satellites had greatly angered Galileo, and had called forth a torrent of invective, in which the Protestant German was abused as a heretic by Galileo, little aware that he would himself, before long, incur the displeasure of the Church. If we could suppose that an unwillingness, either to confirm his rival's