gave stellar spectra. Among the true nebulæ may be mentioned, the Annular Nebula in Lyra; the Dumb-bell Nebula; and the great Nebula in the Sword-handle of Orion—concerning the nature of which there has been so much discussion,
These spectrum investigations afford tangible and unmistakable evidence that there are in space, masses of ignited gaseous or vaporous matter of prodigious extent, shining by their own light, and resembling the vast nebula which the Nebular Hypothesis declares to have been the original condition of our solar system. The nebulous matter, assumed as the basis of the hypothesis, is no figment of the theorist!
What great results have been achieved by the power of means apparently the most trivial! Immense objects, seemingly unattainable, have been grasped by the smallest conceivable handle! A little instrument, which is scarcely any thing more than a small triangular piece of glass, solves questions which hundreds of thousands of dollars expended in telescopes, and years of observation, could not have settled! Penetrating into the illimitable depths of space, it reveals to us something of the physical and chemical constitution of stellar clusters and nebulæ, so remote, that the light which the spectroscope analyzes, must have left them thousands, perhaps millions, of years ago!
The lecturer concluded with the following reflections, which are given without abridgment:
In contemplating the vastness of the sidereal universe, every person, in every age and country, must recognize as irresistibly natural, the train of thought expressed by the Hebrew Psalmist, when he exclaims: "When I consider thy heavens, the work of thy fingers, the moon and the stars, which thou hast ordained; what is man, that thou art mindful of him? and the son of man, that thou visitest him?" (Psalm viii. 3, 4.)
How incalculably has this withering sense of insignificance been augmented by modern telescopic excursions into the remote recesses of the stellar universe! When, by measurements, in which the evidence of the method advances pari passu with the precision of the results, the volume of the earth is reduced to less than one-millionth part of the volume of the sun; when the sun himself, transported to the region of the stars, takes up a very modest place among the thousand of millions of those bodies revealed to us by the telescope; when the ninety-five millions of miles which separate the earth from the sun, by reason of their comparative smallness, have become a base totally insufficient for ascertaining the dimensions of the visible universe, when even the swiftness of light barely suffices for the common valuations of science; when, in short, by a chain of irresistible proofs, certain stars and nebulæ have retired to distances that light could not traverse in less than millions of years we feel as if annihilated by the immensity of the scale of the universe! In assigning to man, and to the planet he inhabits, so small—so insignificant—a position in the
