CIRCLE OF THE SCIENCES WITH SUITABLE REFLECTIONS.

ASTRONOMICAL SKETCHES.-NO. X.-THE MOON.

THE opinions of astronomers are at variance with respect to the existence of a lunar atmosphere. Philosophers often reason from analogy; and because the surface of the Moon bears a striking resemblance to the Earth, in having valleys, mountains, hills, dales, volcanoes, &c. they conclude that the Moon has an atmosphere, and, consequently, rain, hail, snow, and winds. Various are the arguments advanced on each side of this question by astronomers of the greatest fame.

But if we may be allowed to judge from the appearance of the Moon when our nights are clear, we may conclude that the Moon has no atmosphere. No per son ever perceived either clouds or vapours on her disk, or any thing resembling them; and these must have been seen in every age by millions of mankind, if lunar clouds, &c., existed: unless we believe that there may be an atmosphere without vapours.

Mr. Ferguson observes, "If there were seas in the Moon, she could have no clouds, rains nor storms, as we have; because she has no atmosphere to support the vapours which occasion them. And every body knows that when the Moon is above our horizon in the night-time, she is visible, unless the clouds of our atmosphere hide her from our view; and all parts of her appear constantly with the same clear, serene, and calm aspect. But those dark parts of the Moon, which were formerly thought to be seas, are now found to be only vast deep cavities, and places which reflect not the Sun's light so strongly as others, having many caverns and pits whose shadows fall within them, and are always dark on the sides next the Sun, which demonstrates their being hollow: and most of these pits have little knobs, like hillocks, standing within them, and casting shadows also, which cause these places to appear darker than others that have fewer or less remarkable caverns. All these appearances show that there are no seas in the Moon; for if there were any,

their surfaces would appear smooth and even, like those on the Earth."

Dr. Brewster observes, "The arguments adduced by Mr. Ferguson to prove that there is no se a in the Moon are very far from being conclusive. The existence of a lunar atmosphere is completely ascertained; and the little pits and eminences which appear in the dark parts of the Moon, which are extremely even and smooth may be regarded as rocks or islands. By observations, however, on Mare Crisium, when the line which sepa rates the enlightened from the obscure segment of the Moon passed through the large and apparently level spot, I have found that the shaded parts of the Moon, however smooth they may appear, are not level surfaces, and therefore, cannot be seas. If there were seas in the Moon, there would be particular times when the reflected light of the Sun would render them more brilliant than any other part of her surface; and the light would acquire that property called polarization, which is, however, found not to be the case."

It would appear, therefore, from these facts, that there is no water in the Moon, neither rivers, nor lakes, nor seas; and hence we are entitled to infer that none of those atmospherical phenomena which arise from the existence of water in our own globe, will take place in the lunar world.

Every particular connected with the disk of the Moon is interesting, and in many respects, astonishing. Her mountainous scenery is awfully grand. Huge masses of rock rise perpendicularly from the plains, tower to an immense height, and reflect the rays of the Sun as from a steel mirror. These rocks appear perfectly naked, or destitute of any kind of soil and vegetation. In these stupendous and terrific rocks are discovered rents and ravines, as if split or separated asunder by some tremendous earthquake or volcano: and numberless large fragments of rocks are seen near the base of these frightful eminences, as if they had been detached by some extraordinary shock or convulsion.

The surface of the Moon is admirably calculated to reflect the light of the Sun upon the Earth. If her

surface were smooth and level, the reflected light would not have been so luminous and diffusive, and the Earth would have been but indifferently supplied with light in the absence of the Sun. But owing to her surface, this inconvenience is prevented. Her stupendous range of mountains, whose summits rise to an immense height; her lofty, rugged, bare, perpendicular, and in some parts bold and projecting rocks; her numerous, deep and extensive hollows or cavities, containing insular mountains, whose towering tops receive the first rays of the Sun, lofty ridges, or rather mountains, encircling these deep hollows or cavities; all contribute to reflect the rays of the Sun to all sides, and to diffuse light to every part of the Earth in the course of every lunation.

The diameter of the Moon is two thousand one hundred and sixty-one miles; and as solid bodies are to each other as the cubes of their diameters, the magnitude of the Moon is to that of the Earth as one to forty-one.

The Moon is twenty-four thousand miles from the centre of the Earth; and moves from any fixed star to the same star, in twenty-seven days, seven hours, fortythree minutes, and eleven seconds. This is called her

sideral revolution.

Her periodical revolution is the time in which she passes through the twelve signs of the zodiac; or from the equinoctial point to her return to the same. This is performed in twenty-seven days, seven hours, forty-three minutes, and four seconds. The difference between her sideral and periodical revolution is caused by the precession of the equinoxes.

Her synodical revolution is the time in which she passes through her different changes, or from one conjunction with the Sun to the other. This is performed in twenty-nine days, twelve hours, forty-four minutes, and two seconds.

PHILIP GARrett.

Moderation may be considered as a tree of which the root is contentment and the fruit repose.

CABINET OF NATURE.

(Continued.)

VARIETY OF NATURE.

To convey an adequate conception of the number of ideas, as exhibited on the globe in which we live, would baffle the arithmetician's skill, and set his numbers at defiance. We may, however, assist our conceptions a little, by confining our attention to one department of nature; for example, the ANIMAL KINGDOM. The number of the different species of animals, taking into account those which are hitherto undiscovered, and those which are invisible to the naked eye, cannot be estimated at less than 300,000. In a human body there are reckoned about 446 muscles, in each of which, according to anatomists, there are at least ten several intentions, or due qualifications to be observed-its proper figure, its just magnitude, the right disposition of its several ends, upper and lower, the position of the whole the insertion of its proper nerves, veins, arteries, &c. so that in the muscular system alone, there are 4,460 several ends or aims to be attended to.-The bones are reckoned to be in number about 245, and the distinct scopes or intentions of each of these are above 40; in all, about 9,800; so that the system of bones and muscles alone, without taking any other parts into consideration, amounts to above 14,000 different intentions or adaptations. If now, we suppose, that all the species of animals above stated, are differently constructed, and, taken one with another, contain, at an average, a system of bones and muscles as numerous as in the human body-the number of species must be multiplied by the number of different aims or adaptations, and the product will amount to 4,200,000,000. If we were next to attend to the many thousands of blood vessels in an animal body, and the numerous ligaments, membranes, humours, and fluids of various descriptions-the skin with its millions of pores, and every other part of an organical system, with the aims and intentions of each, we should have another sum of many hundreds of millions to be multiplied by the

former product, in order to express the diversified ideas which enter into the construction of the animal world. And, if we still farther consider, that of the hundreds of millions of individuals belonging to each species, no two individuals exactly resemble each other-that all the myriads of vegetables with which the earth is I covered, are distinguished from each other, by some one characteristic or another, and that every grain of sand contained in the mountains, and in the bed of the ocean, as shown by the microscope, discovers a different form and configuration from another-we are here presented with an image of the infinity of the conceptions of Him in whose incomprehensible mind they all existed, during countless ages, before the universe was formed.

To overlook this amazing scene of Divine intelligence, or to consider it as beneath our notice, as some have done if it be not the characteristic of impiety, is, at least, the mark of a weak and undiscriminating mind. That man who disregards the visible displays of Infinite Wisdom, or who neglects to investigate them, when opportunity offers, acts as if he considered himself already possessed of a sufficient portion of intelligence, and stood in no need of such sensible assistances to direct his conceptions of the Creator. Pride, and false conceptions of the nature and design of true religion, frequently lie at the foundation of all that indifference and neglect with which the visible works of God are treated, by those who make pretensions to a high degree of spiritual attainments. The truly pious man will trace with wonder and delight, the footsteps of his Father and his God, wherever they appear in the variegated scene of creation around him, and will be filled with sorrow, and contrition of heart, that, amidst his excursions and solitary walks, he has so often disregarded "the works of the Lord, and the operation of his hands."

In fine, the variety which appears on the face of ‘nature, not only enlarges our conceptions of Infinite Wisdom, but is also the foundation of all our discriminations and judgments as rational beings, and is of the most essential utility in the affairs of human society.