net, which he supposes to arise from the snow lying about those parts.

The surface of Jupiter is distinguished by certain bands or belts, of a duskier color than the rest of his surface, running parallel to each other, and to the plane of his orbit. They are neither regular, nor constant in their appearance; sometimes more, sometimes fewer, being perceived: their breadth varies, and sometimes one or more spots are formed between the belts,

Saturn's distance does not permit us, with common instruments, to distinguish many varieties on his surface, but his ring is a fruitful source for astronomical speculation. Dr. Herschel, by means of his powerful instruments, has discovered a multiplicity of regular belts, which did not change much during the course of his observations. From these he has found, that Saturn has a pretty quick rotation upon its axis, which he has fixed at 10h. 16m. Osec. He has also shewn, that the ring of Saturn is divisible into two concentric rings of unequal dimensions and breadth, situated in one plane, which is probably not much inclined to the equator of the planet. These rings are at a considerable distance from each other, the smallest being much less in diameter at the outside than the largest is at the inside: the two rings are entirely detached from each other, so as plainly to permit the open heavens to be seen through the vacancy between them.

Though much has been unfolded to you in the course of this essay, upon a little consideration, you

will find the things, of which you remain ignorant, infinitely exceed those which you know. It is with us, as with a child, that thinks if he could but just come to such a field, or climb to the top of such a hill, he should be able to touch the sky; but no sooner is he come thither, than he finds it as far off as it was before.

It may perhaps be useful to point out to you the littleness of human knowledge, even in those subjects of which we have been treating; and this I shall dó principally in the words of a late writer.

How far does the universe extend, and where are the limits thereof? Where did the CREATOR " stay his rapid wheels?" where "fix the golden compasses?" Certainly himself, alone, is without bounds, but all His works are finite. He must, therefore, have said, at some point of space,

"Be these thy bounds;

"This be thy just circumference, O world!"

Here the Mathematician must be silent, and wave all calculations, as there can be no ratio between bounded and boundless space, even though the magnitude of the former were taken at the utmost limit man can conceive, or numbers express. But where are the boundaries? Who can tell? All beyond the fixed stars are utterly hid from the children of men.

But what do we know of the fixed stars? A great deal, one would imagine; since, like the MOST HIGH,

we, too, tell their numbers; yea, and call them by their names! But what are those that are named, in comparison with those which our glasses discover? What are two or three thousand, to those we discover in the milky-way alone? How many, then, are there in the whole expanse? But to what end do they serve? To illuminate worlds, and impart light and heat to their several choirs of planets? or to gild the extremities of the solar sphere, and minister to the perpetual circulation of light and spirit?

What are comets? Planets not full formed, or planets destroyed by conflagration or bodies of an wholly different nature, of which we can form no idea. How easy it is, to form a thousand conjectures! how hard to determine any thing concerning them! Can their huge revolutions be even tolerably accounted for, on the principles of gravitation and projection? What brings them back, when they have travelled so immensely far? or what whirls them on, when, reasoning justly on the same powers, they should drop into the solar fire?

What is the sun itself? It is, undoubtedly, the most glorious of all the inanimate creatures: and its use we know. Gon made it to rule the day. It is,

"Of this great world, both eyes and soul."

But who knows of what substance it is composed, or even whether it be solid or fluid? What are the spots on its surface? what its real magnitude? Here is an

unbounded field for conjecture; but what foundation for real knowledge?

What do we know of the feebly-shining bodies, the planets, that move regularly round the sun? Their revolutions we are acquainted with; but who can regularly demonstrate to us either their magnitude, or their distance, unless he assumes it in the usual way, inferring their magnitude from their distance, and the distance from the magnitude. What are Jupiter's belts? What is Saturn's ring? The honest ploughman knows as well, as the most learned

astronomer.

"Sir Isaac Newton certainly discovered more of the dependencies, connexions, and relations of the great system of the universe, than had, previous to his time, been conceded to human penetration : yet, was he forced to bottom all his reasoning on the hypothesis of gravitation; of which he could give no other account, than that it was necessary to the conclusions he rested upon it."

OF THE PRECESSION OF THE EQUINOXES.

The equinoctial points, as have been before explained, are those two opposite points, where the ecliptic and equinoctial cross each other, at the first point of Aries and Libra, and are called the vernal and autumnal equinoxes. By long, and a continual series of observations, it has been observed, that the above two points have a westerly recession, or mo

tion backwards, contrary to the order of the signs of about 50 seconds, yearly, This retrograde motion of the equinoctial points, or the nodes of the earth's orbit, as it has been termed, is called the Precession of the Equinoxes.

The solstitial points, are these two opposite points where the ecliptic touches the tropics, and 90° from the equinoctial points, are consequently subject to the same recession.

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To have a clear idea of this subject, the student must be informed, that astronomers begin the year the spring, when the sun is in that node of the equator, or equinoctial point, called Aries, or at the vernal equinox; and that the time the sun takes in his motion from any one equinoctial point, or tropic, round to the same again, is called the Tropical, or Natural Fear; and called by some the Mean Solar Year. Its length, by observation, is found to be 365 5 48′ 49′′.

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The time the sun also, by observation, is found to take, in moving from any particular star to the the same star again, is called the Siderial Year ; and is fixed at 365 6 9' 12". The siderial year, therefore, exceeds the tropical year by 20 minutes, 23 seconds in time, and consequently the Julian, or Civil Year, which we adopt at 365 days 6 hours, is nearly a mean between the siderial and tropical.

The whole ecliptic of 360° being passed through by the sun in a tropical year, his daily mean motion is about 59' 8"; and for the above difference 20′ 23′′ in time, his motion will be very near 50 ̋; and just