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THE BEAUTY OF THE HEAVENS.

these changes of appearance. We find those spots of the moon, which areconsidered to be mountains or valleys, exhibit appearances which distinctlyprove them to be so. We find that, in all situations of the moon, except thatof her opposition, the more elevated parts constantly produce shadows in adirection opposite to that of the sun, and that the cavities, or depressions, arealways dark on the side nearest the sun, and illuminated on the opposite one;and that the shadows of the convex or elevated portions become progres-sively shorter, as the sun’s light becomes more direct on the surface, while thelower tints of the retiring parts, or cavities, become less dark, by reasonof the same change of direction of the sun’s light. We find that, as anygiven portion of the surface is in progress of removal from the direct illu-mination of the sun, the shadows of its projections, or elevated parts, inva-riably increase in length ; and that, as the light becomes more oblique, thecolour of the cavities becomes still deeper. These appearances, being perfectlyconsistent with what we observe in the case of all surfaces diversified by ele-vations and hollows, satisfy us that such is the actual condition of the moon’ssurface.

These changes, which are continually going on, may be seen in any stage ofa lunation, but are more striking at about seven days before and after the fullmoon. With a telescope of high magnifying power, and under favourable cir-cumstances for the observation, the changes of forms and colour go on with avisible rate of progress. If the observer commence an examination of thiskind w T ith a general view of the entire disc—for which purpose he must use atelescope of low magnifying power, as from twenty-five to forty times—thelarger dark spots, which are visible to the naked eye, resolve themselves intoapparent cavities, distinct spots of minor character, and ramifications of aninfinite diversity of colour and figure. In addition to these he finds other, and,if the subject be entirely new to him, most unexpected and delightful appear-ances. He perceives extensive valleys ; long ridges of mountains, of great ele-vation ; single mountains, occasionally rising to a still greater apparent height;with vast hollows, or excavations in the plains, of the estimated depth of nearlyfour miles, and generally of a singular uniformity of form and character. Itwill be observed that these appearances are not constant, but change theirgeneral character, form, and intensity of colour, with the changes of the moon’splace in her orbit. When she approaches to her opposition with the sun, or thefull, the mountainous elevations, and the depressions of her surface, graduallyincline to a character of more uniformity, while the entire disc assumes a newand equally beautiful appearance. Points of sparkling light, and larger spots ofdifferent degrees of brilliancy, slowly take the place of the rugged and more dis-tinctly marked tracts before observed; and permanent irradiations, of varioustints and brightness, traverse the whole surface, and present a new picture.The scene before us is a representation, on a small scale, of this telescopicgeneral view.

Astronomers, by common consent, distinguish the remarkable spots, moun-