Sun's Surface.

225 the wicked, it does not appear that they had any other foundations than mere opinion and vain surmise; but now I think myself authorised, upon astronomical principles, to propose the sun as an inhabitable world." Sir John Herschel, the son, took a wholly different view as to the coolness of the sun; and, incredible though it seem, regarded certain bright objects, shaped like willow leaves, lying athwart and across each other, as the immediate sources of the solar light and heat. He says "We cannot refuse to regard them as organisms of some peculiar and amazing kind; and though it may appear too daring to speak of such organisations as partaking of the nature of life, yet we do know that vital action is competent to develop at once heat and life and electricity."

The sun's surface has not only spots which have a central part and a fringe less dark; but also contains certain bright streaks, by some called faculæ, in the neighbourhood of the spots. "The sun-spots are really hollows or cavities in the solar atmosphere where the temperature of the glowing gases has been reduced." The spots are said to be confined to two definite zones, extending about 35° on each side of the equator: a scene of solar tornadoes of white-hot hydrogen, which blow with such fierceness that, compared with these, our most destructive storms are summer breezes. The spots are certainly depressions of greater or less depth, and the light received from the umbra of a spot shines through absorbing vapours. "A great difficulty lies in the fact that we have no clear evidence to show whether the sun-spots are formed by forces acting from without or from within, . . . whether the seat of that action which leads to the formation of a spot lies below or above the level of the photosphere. . . . As to the prominences, it seems to be demonstrated that some are mere clouds in the upper regions of the solar atmosphere, while others are due to some form of eruption, and only assume the cloud form after the eruption which gave them birth has ceased." There are bridges, arcs, stalks, leaves, and veils of clouds, most intricate in structure. The wildest and most fantastic variations take place, renewals of fresh forces with Spectrum Analysis," p. 263: Henry E. Roscoe. 2 "The Sun," pp. 438, 439: R. A. Proctor.

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scenes of tremendous tornadoes, swift rushes of glowing vapours and cyclonic motions. The least spot, perceived with the most powerful telescope, has an area of fifty thousand miles; those visible to the unaided eye are enormous. The largest spot recorded had a greater breadth than 143,500 miles. The spots sometimes burst in pieces, like a piece of ice dashed on a frozen pool, and disappear in a moment.

The eruptions, which occur at all times, are vast explosions, seeming to come from some twenty thousand miles below the edge of the sun's disc, and extend many thousands of miles in every direction. There are brilliant, silver, copper, and rubycoloured coruscations. The velocity has been known to exceed two hundred and fifty miles a second. They are of glowing hydrogen, and other vaporous elements, through an atmosphere of hydrogen.

Coloured prominences consist of glowing gas of various tints and forms-their origin is still a mystery. The sierra, or rugged line of projections, is made up of ranges of red and other coloured flames, now called the chromosphere. The whole disc of the sun is much marked with roughness like an orange, and some of the lower parts of the inequalities are blackish. The faculæ are ridges of elevation above the rough surface, and sometimes, next to a spot, will be a protuberant lump of shining matter.

Many metals exist in the sun, more than thirty have been found of the fifty-one known on earth. The sun is made chiefly of metals; in our earth metals form the minority.

The surface of the sun is exceedingly complex. Analysis of spots shows three envelopes within the photosphere: the penumbral fringe, the dark umbra, the so-called black nucleus about ten thousand miles below the photosphere. The photosphere is a fourth solar level. The fifth is a shallow atmosphere discovered by Young, extending three or four hundred miles above the photosphere. Sixth, the sierra, about eight or ten thousand miles. Seventh, the prominence region, extending to a height of thirty or forty thousand miles, with occasional extension to more than a hundred thousand miles. Eighth, the inner brighter corona, from two to three hundred thousand miles, expanding in places to four

Counterpart in the Planet Saturn.

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or five hundred thousand miles. Ninth, the outer radiated corona, jagged in outline and extending fully a million of miles from the visible glowing surface of the sun. All these envelopes are themselves multiple; and the outer corona is but the inner part of a solar envelope, or appendage, with outermost limits lying altogether out of ken. What a complex subject of research lies before our astronomers!

The sun has almost a counterpart in the planet Saturn, whose splendid architecture displays the fashioning power of the great laws of the universe. The beauty of the system, the marvellous gigantic rings, the delicate varieties of colours in the rings and in the planet, the singular problems suggested by their magnificent size, fascinate the observer. If the vast belts are not cloud-masses formed by the sun, their real origin must be in some action of the planet's own mass. The heat of his surface may cause currents of vapour to rise continually; on attaining the upper regions of his atmosphere, they are condensed in the form of a cloud. "A similar peculiarity exists in the case of the sun. Indeed, a somewhat surprising resemblance exists between Saturn and the sun, as regards many important characteristics. The planet, like the sun, is of low specific gravity-very far lower than the earth's; as the sun has eight primary attendants, so Saturn has eight satellites; and as the sun has his attendant disc of minute bodies (seen in the Zodiacal light), so Saturn has his ring system, in all probability, of multitudes of minute satellites. travelling in independent orbits around him. Is it not possible that the relation necessary to make the analogy complete may be actually fulfilled, and that Saturn is a source whence heat is supplied to the orbs which circle around him ? "1

The analogy may be added to by a further fact-Jupiter, with his dark bands, seems now to be in the same state as was our earth. His cloudy shifting streaks; and the appearance, at times, as of mountains or openings; may be inaugurating new days and nights in that far-off mighty planet.

It is not necessary, for those who believe that all things are of God, to adopt any scientific theory as final. Mayer and Thomson maintained that the sun's heat, compared with 1 "Essays on Astronomy," p. 99: R. A. Proctor.

which the fiercest fire of a mass of white-hot iron is cold as ice, is sustained by the continual infall of cosmical bodies. Helmholtz supposes that gradual contraction of the solar orb is the mainspring of solar energies. Secchi believed that the fund of force lies in the union of the sun's own elements in chemical combinations. Sir John Herschel said, that mayhap the vital energies of monstrous creatures are the source of the luminary's might. The facts are so wonderful that even a sober explanation must appear wild, discovered realities are more sublime than any fictions that were ever addressed to the imagination.

The Sun's Rule.

He draws to himself all such cosmical matter and bodies as come under his exclusive influence, either by leaving the domain of some other star, or on account of his own motion through space. These do not all remain with him; but, after paying their respects, return to the sidereal depths to be attendants on other suns and stars, to perform functions in many worlds. Around him are millions of millions of bodies of varying velocities in different directions; clouds of cosmical atoms shifting and changing, aggregating here, segregating there; but, as a clustering solar appendage, permanent-an aureola of tremendous dimensions and startling magnificence. The meteors encountered by our earth every year are upwards of 2,700,000 visible to the naked eye; including shooting stars, only seen by telescopic aid, the hypothetical sum is 146,000,000,000. The space between the earth's orbit and the sun cannot be less rich; in fact, there must be an increasing aggregation of meteoric matter as the solar globe is approached.

By the exercise of his mighty attractive influence, he controls the force which would drive planets and meteors far out into space from the influence of his lighting, heating, actinic influence. So perfect his government, that the processes of slow change take place within limits, and the continual variations produce permanence in paths ever varying around him. By slowly exerted influence, he changes the eccentricity of our earth's orbit, causes the terrestrial equinoxes to circuit the ecliptic in their grand precession of 25,868 solar years;

continents become oceans, and seas dry land; one hemisphere and then another supplies fruitful fields; activity follows rest, and rest activity; during many ages, the globe has been, and will continue to be, a fit abode of life and beauty.

In one sense the sun's sphere of influence includes all space, but for practical purposes we regard it as limited and definite. His power is 315,000 times greater than the earth's. It might be supposed that a very vast increase of velocity is needed to change our periodic revolution; but if the earth's speed were raised from its actual rate, 182 to 19 miles the second, to about 25.7 miles the second, we should be carried thenceforth further and further away from light and life. Still rotating, day and night still succeeding, the orderly sequence of the seasons would be displaced by continual diminution of solar light and heat; a cold more intense than that of the bitterest Arctic winter would bind all things in everlasting frost. So true is it, the lights in heaven are for signs and seasons, for seed-time and harvest, for summer and winter.

The sun rules all the vapour of our atmosphere, lifting it up, then casting it down as rain or snow. The mechanical power of every river in the world, the energy of the winds, the growth of trees and vegetables, the support of animal life, are all from him. The blood in our veins-that oil of the lamp of life, the work of our muscles, the oxidation which supports the heart's action-without which it would be utterly consumed by its own action in eight days, prove that we are children of the sun. In tracing out all these powers to their source, we come to one power-the sun. He is the natural agent, and it is as easy for men to see the Providence of God in the natural ordering of the world, as in startling and miraculous occurrences.

For many æons the sun and our earth were "a fluid haze of light;" then again, for other æons, our earth, like the sun, was a globe instinct with fiery heat in which no life could live after the manner of life now known. The potential germs of life might have been present in the midst of the fire, but only after periods infinite to our conception could life, such as we know it, or in the remotest degree like it, begin to exist. It is probable, however, from the fact that seeds, in order to