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form very uncertain and random conjectures concerning it; yet, from the infinite variety which we find in the works of the creation, it is not unreasonable to suspect, that very possibly some of the fixed stars may have so little natural brightness in proportion to their magnitude, as to admit of their diameters having some sensible apparent size when they shall come to be more carefully examined, and with larger and better telescopes than have hitherto been in use.

'With respect to the Sun, we know his whole surface is extremely luminous, a very small and temporary interruption sometimes, from a few spots, excepted. This universal and excessive brightness of the whole surface is probably owing to an atmosphere, which being luminous throughout, and in some measure also transparent, the light proceeding from a considerable depth of it all arrives at the eye, in the same manner as the light of a great number of candles would do if they were placed one behind another, and their flames were sufficiently transparent to permit the light of the more distant ones to pass through those that were nearer without interruption.

"How far the same constitution may take place in the fixed stars we do not know; it may in some, but, with regard to others, it does not seem to be the case, particularly in those which are, in some degree, periodically more or less luminous; and also in those which have sometimes appeared and disappeared: and if those conjectures are well founded, which have been formed by some philosophers concerning stars of this kind, that they are not wholly luminous, or at least not constantly so, but that all, or by far the greatest part, of their surfaces is subject to considerable changes, sometimes becoming luminous, at others extinguished; it is among stars of this sort that we are most likely to meet with instances of a sensible apparent diameter, their light being much more likely not to be so great in proportion as that of the Sun, which, if removed to 400,000 times his pre

sent distance, would still appear, I apprehend, as bright as Sirius, as have been observed; whereas it is hardly to be expected, with any telescope whatever, that we should ever be able to distinguish a well defined disk of any body of the same size with the Sun, at more than 10,000 times his present distance.'

Hence the greatest distance at which it would be possible to distinguish any sensible apparent diameter of a body as dense as the Sun, cannot well greatly exceed five hundred times ten thousand; that is five million times the distance of the Sun; for if the dia meter of such a body were not less than 500 times that of the Sun, its light, as has been shown, could never arrive at us.

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Dr. Herschel, improving on Mr. Michell's idea of the fixed stars being collected into groups, and assisted by his own observations with telescopes of extraordinary powers, has suggested a theory concerning the construction of the universe, which was as ingenious as it was new. It had been the opinion of former astronomers, that our Sun, besides occupying the centre of the system which properly belongs to him, occupied also the centre of the universe; but Dr. Herschel is of a different opinion. Hitherto,' says he, the sidereal heavens have (not inadequately for the purpose designed) been represented by the concave surface of a sphere, in the centre of which the eye of the observer might be supposed to be placed. It is true, the various magnitudes of the fixed stars even then plainly suggested to us, and would have better suited, the idea of an expanded firmament of three dimensions; but the observations upon which I am now going to enter, still farther illustrate and enforce the necessity of considering the heavens in this point of view. In future, therefore, we shall look upon those regions into which we may now penetrate by means of large telescopes, as a naturalist regards a rich extent of ground or chain of mountains containing strata variously inclined and

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directed, as well as consisting of very different materials. The surface of a globe, therefore, will but ill delineate the interior parts of the heavens.'

The Sun's rising and setting for certain days this month will be as follow; viz. on the

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Equation of Time.-The following table will point out what is to be subtracted from apparent time, to obtain equal or true time for every 5th day of the month:

m. s.

Thursday, Sept. 1, from the time on the dial SUBTRACT O

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Sunday,- - 11,

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Tuesday,

Friday,

Wednesday,

Monday,

- 16,

2

1 38

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The Sun enters the sign Libra on the 23d, at 55 m. past 4 in the afternoon.

The Moon enters its last quarter on the 7th day of Sept. at 34 m. past 5. The change, or New Moon, occurs at 18 m. past 11 at night on the 13th. This enters its first quarter on the 21st, at 41 m. past noon, and the Moon is at its full at 53 m. past 11 in the forenoon of the 29th.

The time of the Moon's rising for the five first days after the time of being full on the 30th of August, referred to before, will be as follows:

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The planet Venus will eclipse, on the 15th, the star; and on the 20th, she will eclipse. On the 27th, the Moon will eclipse the star marked 3 The immersion will occur at 55 m. past 7 in the evening, and the emersion at past 8; the star, in both cases, being 13' north of the Moon's.

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centre. In the interval, viz. at 8 m. past 8, the Moon will be in conjunction with the star 2 ↓ The planet Jupiter is stationary on the 28th this planet is now too near the Sun to admit of any eclipses of its satellites being visible. Mercury's superior conjunction will be at past 9 on the 21st: there will be a conjunction of Mars with the Sun at past 8 in the morning on the 2d; and one of Jupiter at 3 in the morning on the 14th.

VIEW OF THE SOLAR SYSTEM. Of the four newly-discovered planetary Bodies, Ceres, Pallas, Juno, and Vesta.

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It was believed, till the present century, that the planet Jupiter was next to Mars in the solar system. On the 1st of January, 1801, the planet Ceres was discovered at Palermo, in Sicily, and since that, at. different periods, three other small planetary bodies have been found to exist, whose orbits are between those of Mars and Jupiter: of these, we shall give an account in their order, according to the dates of their discovery. The planet Ceres, when first seen, was observed to be in Taurus: the nebula with which it was apparently surrounded, gave it the appearance of a comet; and it was in consequence of the suggestion of Professor Bode of Berlin, or of Baron Zack, that Piazzi, and other astronomers, ranked it among the planetary bodies.

The planet Ceres is of a ruddy colour, and with a proper telescope it appears about the size of a star of the 8th magnitude. It seems to be surrounded with a large dense atmosphere, and plainly exhibits a disk when examined with a magnifying power of about 200. This planet is situated between the orbits of Mars and Jupiter. She performs her revolution round the Sun in four years, seven months, and ten days, and her mean distance from that body is nearly 260 millions of miles. The eccentricity of her orbit is not very great, but its inclination to the ecliptic ex

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ceeds that of all the old planets. The length of its diameter was thought by Dr. Herschel not to exceed 160 miles, but, according to Schroeter, it is more than ten times that length.

Pallas, the next planet in order, was discovered at Bremen, in Lower Saxony, on the 28th of March, 1802, by Dr. Olbers, the same active astronomer who re-discovered Ceres, after it had been lost to M. Piazzi and others. Pallas is situated between the orbits of Mars and Jupiter, and is nearly of the same magnitude with Ceres, but in colour it is less ruddy: it is surrounded with a nebulosity of almost the same extent, and performs its annual revolution in about the same period. The planet Pallas, however, is distinguished in a remarkable manner from Ceres, and all the other primary planets, by the immense inclination of its orbit. While these bodies are revolving round the Sun in almost circular paths, rising only a few degrees above the plane of the ecliptic, Pallas ascends above this plane at an angle of about 35 degrees. From the eccentricity of Pallas being greater than that of Ceres, while their mean distances are nearly equal, the orbits of these two planets mutually intersect each other, a phenomenon which is altogether without a parallel in the solar system. The diameter of Pallas has not been determined with accuracy there is, indeed, a great discordancy in the opinions of the English and German astronomers; Herschel making it only 80 miles, while Schroeter makes it no less than 2099 miles.

The planet Juno, the third of the newly discovered planets, was observed first by Mr. Harding, at the observatory of Lilienthal, near Bremen, on the evening of the 1st of September, 1804. While this. astronomer was forming an atlas of all the stars which are near the orbits of Ceres and Pallas, he observed in the constellation of Pisces a small star of the 8th. magnitude, which was not mentioned in the Histoire Celeste of La Lande; and, being ignorant of its lon

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