CHAPTER VII.

LECTURE II.-NATURE VS. COPERNICUS.

WE MAY perhaps at some time have seen a beautiful edifice, whose superstructure was correct, both in outline and detail:magnificent in proportions, artistic in design, gorgeous in decoration, admired by all beholders; the pride of its architect and builders; -- yet resting on an unsound base: rendering it desirable, for the public good, that its instability be known of men.

May the honored dead, and their living representatives, forgive my presumption in concluding that such is the noble monument of thought and observation and calculation, which we are about to examine; and which has been built, block added to block, by men whose genius and culture would sink in ignominy and despair my poor dwarfed, meager attainments. But remembering it is for

the Master, I must press forward; waiting for justification, if must needs be, till that time when we shall know, even as we are known; and when our spiritual eyes may be able to discern the pure motive often lying beneath the halting, unsuccessful, or perchance mistaken deed.

Maintaining that the foundation of such a structure should be God and his revealed Word, with the operations of Nature, correctly observed, as material for the building of the superstruction, we will now proceed to investigate as to the solidity of the corner blocks on which men have builded this tower to the skies.

THE REFRACTION OF LIGHT.

If we hold a straight rod in the water obliquely, we observe that the part below the surface appears to be bent upward; but knowing, from the firmness of the rod, that this is not really so, we are led to discover that the rays of light passing through the two media of air and water, are bent downward at the water line. This, we all under

stand is called the Refraction of Light; and takes place whenever light passes from a rarer to a denser medium, and vice versa ; the degree of refraction depending on the obliqueness of the rays, and the difference in density of the media.

In considering the light-refracting properties of our atmosphere, we might treat it as consisting of an infinite number of strata, each lower stratum a trifle denser than the one above it; which would have the effect (as it really does have) of bending rays of light passing obliquely through it, into that infinite number of angles which constitute a curve; the curvature or refraction being greatest at the horizon, and decreasing rapidly toward the zenith, where it disappears altogether. So great an obstacle has this proven to correct observation of the heavens that Sir. Geo. Airy, England's Astronomer Royal, termed it The bane of astronomers; and in my simplicity I shall go still farther, by calling it the vail which God has drawn between the known, and the unknown and unknowable.