THE MOON.

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it shines in its meridian splendour vertically down upon theinterior plain, almost every shadow disappears. Then thelengthening shades of the jagged western summits begin tocreep up the eastern slopes. Soon the last lingering rays oflight vanish from the scene, and we wait for another lunationin which to watch afresh.

The most important points which may thus be observedin these formations, are their vast diameters, the great heightand terraced character of the ring by which they are bounded,the frequent occurrence of a deep depression of the interiorplain below the surrounding level, and of conical elevationsin its midst. Most of these characteristics, as well as manyother interesting features and formations upon a smaller scale,may be seen in the view of the lunar mountain Copernicus and its surroundings (see Plate VI.), which by Mr. Nasmyth’skind permission we present to our readers. It is reduced fromthat published in his and Mr. Carpenter’s well-known andcostly treatise upon the Moon , the original photograph havingbeen taken from a plaster model most carefully formed, theappearance and the shadows cast by the ditferent parts ofwhich, when it was placed in a strong light, exactly agreedwith the view of the corresponding portion of the Moon seenwith a powerful telescope.

In addition to the large ring-mountains, to which ourdescription has, so far, chiefly referred, there are some whichextend in a longitudinal direction, and consequently morenearly resemble the mountain chains with which we arefamiliar upon the Earth . Two of the largest of these arerespectively named the Lunar Alps and Apennines . If theMoon , when about half-full, be looked at through a telescope,which, by the reversing action of its lenses, will in our latitudemake its northern parts appear to be the lowest, the Alps willbe seen about ^th, and the Apennines about |rd, of the way upits inner edge. The Apennines are the more extensive andremarkable of the two ranges, their length being about 430miles, and their loftiest peaks some 18,000 feet in height;while the highest of the Alps (called, after its sister peak uponthe Earth , Mont Blanc) scarcely exceeds 12,000 feet. Many