from an incandescent solid or liquid, absorb exactly the same rays which they would themselves emit if incandescent. Light shining through the vapors of sodium presents a certain set of dark lines; but if the vapors of sodium are rendered incandescent, they produce a set of bright lines occupying exactly the places of the dark ones. This set of dark lines across any spectrum becomes, therefore, the evidence of the presence of sodium in the vapors through which the light passes. Now, dark lines, as we said, cross the spectrum of the sun. This, first of all, proves that the light of the sun emanates from an incandescent solid or liquid, and passes through vapors of lower temperature in escaping to the earth. How sudden and unexpected a revelation of its constitution! A liquid nucleus with an envelope of glowing clouds.* But certain ones of these dark lines occupy exactly the positions of the bright lines of the spectrum of sodium. The vapor of sodium is therefore present in the gaseous envelope of the sun! Sodium is one of our most common substances. It is the basis of common salt consumed at every human meal. gives the saltness to the waters of the universal ocean. This most familiar element enters largely into the constitution of the sun. But another set of the dark lines of the solar spectrum corresponds to the bright lines of the spectrum of hydrogen. Now hydrogen is one of the two constituents of all the water which belongs to our planet. It is also a constituent of coal, of petroleum, and of all vegetable and animal substances. This familiar element abounds also in the sun! Nor is this all. Physicists have studied these magical lines of the solar spectrum until they have detected the existence of sundry other substances in the constitution of the sun. We find there not only sodium and hydrogen, but iron, magnesium, barium, copper, zinc, calcium, chromium, nickel, and prob *Father Secchi does not regard the liquid nucleus fully proven. The dark spectral lines would result if the photosphere of the sun were in such a state of condensation as to present an analogy to mist, and thus shine as a liquid; while the absorbent medium might be a non-luminous atmosphere external to the photosphere. Thus the central portion of the sun might be a non-luminous gas, (Secchi: "Op. Cit.," pp. 104-6.) Though this theory is adopted by M. Faye, ("Comtes rendus," 16 and 23 Jan., 1865; 27 July, 1868, tom. lxviii, 197,) we feel constrained to regard the doctrine of a molten nucleus the most plausible. ably, also, cobalt, strontium, cadmium, and potassium. These include nearly all our common elements. Iron is disseminated through all the rocks, and, in places, is accumulated in mountain masses. Calcium is the basis of chalk and all limestones, and enters into the constitution of a large proportion of the other rocks. Magnesium, under the guise of dolomite, constitutes extensive geological formations, and enters, besides, as a common constituent, into other minerals and rock-masses. Verily, it would seem that earth and sun have been molded out of the same lump of material. Were earth a daughter of the sun, she could not more completely have inherited the traits of her mother. With what breathless interest were the questionings of this little instrument addressed to the stars! And how satisfactorily did they respond! Dark lines cross their spectra as in that of the sun. They are, then, other suns; they shine by their own light; their luminous spheres are enveloped in vapors, whose light-vibrations are attuned in unison with those excited by the spheres themselves. But what are the substances whose interferences silence certain of these starry rays? Are they known, or are they stranger elements? How sublimely instructive the response, as we see it handed down from Aldebaran and Betelguese and Sirius. Sodium is also there, and magnesium and iron and calcium. Yes, one kind of matter forms the substance of the solar system and the starry firmament. The dust of our streets is ignited to starry suns in Arcturus and the Pleiades. There is one step further. Will the nebula respond to our interrogatories? We do not mean the revolvable nebulæ for these, of course, will give us star-light; but what of the cloudy nebula which stubbornly refuse to be resolved? They have sent down their response; the lines of their spectra are * *There are, indeed, resolvable nebula which give us bright-line spectra. Their separate stars are therefore merely segregated patches of the luminous vapor, which in many cases appears more continuous in the regions more removed from the center. These phenomena are full of suggestions bearing upon theories of stellar genesis. It may be as well to add that not a few celestial objects afford us a continuous spectrum-having neither bright nor dark lines. This is true of several dense star-clusters, as well as of a number of resolvable nebulæ. The continuous spectrum may indicate that these bodies are incandescent solids or liquids, or bright instead of dark! They are luminous vapors. How promptly and how eagerly they testify. How long have they waited for this opportunity to reveal the vastness of the ONE CREATOR'S empire! These cloudy nebulæ are not, then, other firmaments of stars, but starry material to be wrought hereafter into firmaments. But what of the substance of these vapors? We confess that here are phenomena which, for the present, puzzle us. The analysis of the thin light of a nebula is a most difficult task, and we are but just beginning to succeed. Still, in these revelations are two words, and perhaps three, which we recognize. In the (planetary) nebula of Draco are bright lines, which correspond to nitrogen and hydrogen, and one which comes very near to barium. It should be remarked, in conclusion, that the failure to identify any terrestrial substance in a celestial body is not conclusive proof against its existence; since, in the case of luminous bodies enveloped in luminous vapors, the luminosity of the vapor may be such that its emissive property exactly neutralizes its absorbent property, so that the spectrum shows neither the dark lines nor the bright lines characteristic of the vapor. For the purpose of furnishing a convenient conspectus of the results attained from the spectroscopic analysis of a large range of luminous objects, we append to this article a table compiled from the leading authorities. Such are the principal facts which the most recent studies in cosmical physics have revealed respecting the unity of the material universe. We cannot fail to be impressed by the validity of the conclusion, and the importance of the lesson which it teaches respecting the unity of that intelligence and power and personality of whose will all these phenomena are the objective expression and interpretation. The phenomena which we have surveyed and reasoned about are all facts of co-existence. There is a co-ordinate view of unity in nature which presents facts in an order of succession, contemplating every phenomenon as a stage in a single devel else, that having gaseous envelopes like the ordinary stars, these envelopes are in just that state of luminosity and tension which renders their emissive power equal to their absorbent. Such a state of vaporous luminosity would, therefore, exceed that of our sun. (Compare Proctor: "Other Worlds than Ours," pp. 289-292.) opmental line stretching backward and onward toward eternity. Such a survey is adapted to leave upon the mind an impression of the unity of the controlling Intelligence through boundless time, as vivid as the glimpse we have taken is fitted to impress respecting the unity of that Intelligence in boundless space. That survey, which is complementary to the present one, and which brings us into the presence of the question of cosmical evolutions, must be deferred to another occasion. 1 The chromosphere of the sun contains sodium, hydrogen, magnesium, and barium. Secchi: "Le Soleil." Secchi: "Le Soleil." Huggins: "Spectral Analysis of the Heavenly Bodies." Huggins: Phil. Trans., 1868. See also "Comte's rendus," lxvi, pp. 1299 and 1836. Alcxander Herschel. ART II.-CHRISTIAN PURITY. The Nature and Blessedness of Christian Purity. By Rev. R. S. FOSTER. New York. 1851. Christian Purity; or, The Heritage of Faith. Revised, Enlarged, and Adapted to Later Phases of the Subject. By Rev. R. S. FOSTER, D.D., LL.D. New York. 1869. MAX MULLER, in his lectures on the "Science of Religion," has well said that "the intention of religion, wherever we meet it, is always holy. However imperfect, however childish a relig ion may be, it always places the human soul in the presence of God; and however imperfect or childish the conception of God may be, it always represents the highest ideal of perfection which the human soul for the time being can reach and grasp. It lifts the soul above the level of ordinary goodness, and produces at least a yearning after a higher and better life—a life in the sight of God." In like manner we conceive that the means which all religions employ are designed to secure the end which they contemplate, and to bring the soul into the possession of that for which it yearns. Hence, the erection of temples, the institution of priesthoods, the offering of sacrifices, as well as all the pilgrimages, ablutions, fastings, penances, mortifications, and prayers which they have enjoined, were for the purpose of enabling the soul to realize its own ideal of goodness and purity. It cannot be doubted that the consciousness of sin and guilt has burdened human hearts in all ages and in all climes. During all the centuries a bondaged world has been groaning for deliverance-crying out in its agony or despair, in one form or another, "What must we do to be saved?" Nor can we fail to notice that all these systems of religion, following only the light of nature, or the crude traditions which they have embodied, whatever the means which they have employed, whatever their intention may have been, have left the nations in disquiet and unrest, failing utterly to "make the comers thereunto perfect." The stream will not rise higher than the fountain; and no human soul will ever rise above the level of the god which it worships, or the ideal of the system of religion which it embraces. Hence, the history of the world demonstrates clearly that the various systems of heathenism |