Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: LECTURE II. THE ORIGIN OF OUR GLOBE ASTRONOMICALLY AND GEOLOGICALLY CONSIDERED, AND THE MOSAIC HISTORY OF IT JUSTIFIED AND DEFENDED BY SCIENCE. If I am diffuse in my remarks, and the chain of argument appears protracted and attenuated, my justification is, in the novelty of the positions I take, and the necessity of being very explicit in their defence. For this reason I shall quote from Burritt a condensed view of all the various discoveries which have been made with regard to the nebulae, so that we may have, in one view before us, every aspect of the subject, which has either a favorable or an unfavorable bearing upon our theory. "The nebulae, so called from their dim, cloudy appearance, form another class of objects which furnish matter for curious speculation and conjecture, respecting the formation and structure of the sidereal heavens. When examined with a telescope of moderate powers, the greater part of the nebulae are distinctly perceived to be composed of little stars, imperceptible to the naked eye, because, on account of their apparent proximity, the rays of light proceeding from each are blended together, in such a manner as to produce only a confused luminous appearance. In other nebula?, however, no individual stars can be perceived, even through the best telescopes; and the nebulae exhibit only the appearance of a self- luminous or phosphorescent patch of gaseous vapor, though it is possible that even in this case, the appearance may be owing to a congeries of stars so minute, or so distant, as not to afford, singly, sufficient light to make an impression on the eye. In some instances a nebulae presents the appearance of a faint luminous atmosphere, of a circular form, and of large extent, surrounding a central star of considerable brilliancy. One o...