Page:Popular Science Monthly Volume 3.djvu/589

From Wikisource
Jump to navigation Jump to search
This page has been validated.
573
OLD CONTINENTS.

It would be unwise to theorize at present on a result so remarkable. Nor can we assert that Herschel's speculations have been confirmed, though his general reasoning has been abundantly justified. Astronomers have yet to do much before they can interpret the mysterious entity which adorns Orion's sword. On every side, however, observations are being made which give promise of the solution of this and kindred difficulties. We have seen the light of comets analyzed by the same powerful instrument; and we learn that the light from the tail and coma is similar in quality (so far as observation has yet extended) to that emitted from the Orion nebula. We see, therefore, that in our own solar system we have analogues of what has been revealed in external space. I would not, indeed, go so far as to assert that the Orion nebula is a nest of cometic systems; but I may safely allege that there is now not a particle of evidence that the nebula lies beyond our galaxy.

Nor need we doubt the accuracy of Lord Rosse's observations. More than a year before his death, indeed, he mentioned to Dr. Huggins that "the matter of the great nebula in Orion had not been resolved by his telescope. In some parts of the nebula he observed a large number of exceedingly minute red stars. These red stars, however, though apparently connected with the irresolvable blue material of the nebula, yet seemed to be distinct from it."

The whole subject seems to be as perplexing as any that has ever been submitted to astronomers. Time, however, will doubtless unravel the thread of the mystery. We may safely leave the inquiry in the hands of the able observers and physicists whose attention has been for a long time directed toward it. And we need only note, in conclusion, that in the Southern Hemisphere there exists an object equally mysterious—the great nebula round η Argus—which has yielded similar results when tested with the spectroscope. The examination of this mysterious nebula, associated with the most remarkable variable in the heavens a star which at one time shines but as a fifth-magnitude star, and at another exceeds even the brilliant Canopus in splendor may, for aught that is known, throw a new light on the constitution of the great Orion nebula.—Fraser's Magazine.

 

OLD CONTINENTS.
By Prof. A. C. RAMSAY,

OF THE ENGLISH GEOLOGICAL SURVEY.

FOR many years the stratified formations in general were described in manuals of geology as of marine origin, with the exception perhaps of part of the Coal measures, and more unequivocally of the Purbeck and Wealden beds, and the fresh-water strata of parts of the Eocene and Miocene series. Even now the Old Red