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tances.

prove the pears to us. The astonishing length that this comet stars to be runs out into empty space, suggests to our minds at im.

an idea of the vast distance between the Sun and mense dis- the nearest fixed stars; of whose attractions all the

comets must keep clear, to return periodically, and go round the Sun; and it shews us also, that the nearest stars, which are probably those that seem the largest, are as big as our Sun, and of the same na. ture with him; otherwise, they could not appear so large and bright to us as they do at such an im. mense distance.

94. The extreme heat, the dense atmosphere, the Inferenc. es drawn gross vapours, the chaotic state of the comets, seem from the at first sight to indicate them altogether unfit for the

.
purposes of animal life, and a most miserable habi-
tation for rational beings; and therefore some* are
of opinion that they are so many hells for torment-
ing the damned with perpetual vicissitudes of heat
and cold. But when we consider, on the other hand,
the infinite power and goodness of the Deity; the
latter inclining, the former enabling him to make
creatures suited to all states and circumstances; that
matter exits only for the sake of intelligent beings;
and that wherever we find it, we always find it preg-
nant with lise, or necessarily subservient thereto;
the numberless species, the astonishing diversity of
animals in earth, air, water, and even on other ani-
mals; cvery blade of grass, every tender leaf, eve-
ry natural fluid, swarming with life; and every one
of these enjoying such gratifications as the nature and
state of each requires : when we reflect, moreover,
that some centuries ago, till experience undeceived
us, a great part of the Earth was adjudged uninhabi.
table; the torrid zone, by reason of excessive heat, and
the two frigid zones because of their intolerable cold;
it seems highly probable, that such numerous and

* Mr. Wurston, in his Astronomical Principles of Religion.

large masses of durable matter as the comets are, however unlike they be to our Earth, are not destitute of beings capable of contemplating with wonder, and acknowledging with gratitude, the wisdom, symmetry, and beauty of the creation ; which is more plainly to be observed in their extensive tour through the heavens, than in our more confined circuit. If farther conjecture be permitted, may we not suppose them instrumental in recruiting the expended fuel of the Sun; and supplying the exhausted moisture of the planets? However difficult it may be, circumstanced as we are, to find out their particular destination, this is an undoubted truth, that wherever the Deity exerts his power, there he also manifests his wisdom and goodness.

ble.

95. THE SOLAR SYSTEM, here described, This sys. is not a late invention; for it was known and taught ancient by the wise Samian philosopher PYTHAGORAS, and deand others among the ancients : but in latter times monstrawas lost, till the 15th century, when it was again restored by the famous Polish philosopher, NichoLAUS COPERNICUS, born at Thorn in the year 1473. In this he was followed by the greatest mathematicians and philosophers that have since lived; as KEPLER, GALILEO, DESCARTES, GASSEN DUS, and Sir ISAAC NEWTON; the last of whom has established this system on such an everlasting foundation of mathematical and physical demonstration, as can never be shaken; and none who understand him can hesitate about it.

96. In the Ptolemean system, the Earth was sup- The Ptoleposed to be fixed in the centre of the universe ; mean sysand the Moon, Mercury, Venus, the Sun, Mars, surd. Jupiter, and Saturn, to move round the Earth. Above the planets, this hypothesis placed the firmament of stars, and then the two crystalline spheres: all which were included in and received motion from the primum mobile, which constantly

K

chonic

revolved about the Earth in 24 hours from east to west. But as this rude scheme was found incapable of standing the test of art and observation, it was soon rejected by all true philosophers; notwithstanding the opposition and violence of blind

and zealous bigots. The 'Ty. 97. The Tychonic system succeeded the Ptolosystem

mean, but was never so generally received. In this partly the Earth was supposed to stand still in the centre true, and of the universe or firmament of stars, and the Sun partly false. to revolve about it every 24 hours; the planets,

Mercury, Venus, Mars, Jupiter, and Saturn, going round the Sun in the times already mentioned. But some of Tycho's disciples supposed the Earth to have a diurnal motion round its axis, and the Sun with all the above planets to go round the Earth in a year; the planets moving round the Sun in the aforesaid times. This hypothesis being partly true and partly false, was embraced by few; and soon gave way to the only true and rational system, restored by COPERNICUS, and demonstrated by Sir Isaac Newton.

98. To bring the foregoing particulars into one point of view, with several others which follow, concerning the periods, distances, magnitudes, &c. of the planets, the following table is inserted.

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A TABLE of the Periods, Revolutions, Magnitudes, &c. of the Planets, on the Supposition of the Sun's Parallax being 10". Por their nearly true
distances from the Sun, as determined from observations of the transit of Venus, in the year 1701, see § 194.
Diame. Mean) Mean dis-

Axis
Eccentricit

Orbit

Place of Propor. P.opor. Prop.on
D.urnal
Sun and Annual period

Propor
ter in diam. as tance from

tion of Lion of gravity |tion of
of its orbii inclined inclined Place of its its as-
rotationon
Planets. round the Sun.
English seen fr. the Sun in

to its
in miles.

to the its axis.

aphelion. cending diame- magni. on the

density miles the Sun. English miles

orbit. ecliptic

node. ters. tude surface. SUN

. 25d. 6h 1 763000

89 O'

10000 | 877650 24 25,5 Mercury 87d. 236. Unknown 2600 20" 32,000,000

6,720,00 Unkn. 6° 54' 1 130 88 14° 43'1 34.1 .097 Unkn. Unkn.
Venus 224d. 17h. 24d. 8h 7906; 30"

59,000,0001
413,000 750

0' 3° 20' 40 20 13° 59' 103.5 1 Unkn. Unkn.
Earth 365d. 6h id. 011 7970 21" 82,000,000

1,377,000123° 29'|

i 80 111 104.5 1

1 100
Moon 365d. 6h. 29d 12.11h 21801 6"

82,000,000!
13,000! 2° 10' 5° 18'

Variable, 28.5 .02 .34 123.5
Mars 686d. 6h. 1:4h. 40m

4444 11"

125,000,000 11,439,00000 0'l 1° 52' m 9° 10'18 17° 17' 58.17 .2 Unkn. Unkn. Jupiter 4332d. 12h. 9h. 56m.

81000 37" 426,000,000 20,352,000 00 0' 1° 20' 27° 50' 7° 29' 106,67 1049 2

19 Saturn 10759d. 7h. 10h, 16m.

67000

16" 780,000,000 42,735,000 Unkn. 2° 30' 1 27° 50' 621° 13' 878,11 586 1.5 15 Georgian/ 30456d. 26. Unknown 35000 9,9"

1565,000,0001 74,404.000Unkn. 0° 46'1* 13° 12'10 12° 49' 448.431 79.67 1.17 22 Propor- Propor. Hourly Hourly

Projectile

Periods round Periods round Periods round

force being
Sun and tion of quanti- motion motion Square miles in
Planets. light & ty of
Cubic miles in solidity. | destroyed,

Saturn.
in its of its e.

Jupiter.

the Georgian.
surface.
heat. matter. orbit. quator.

would fall

to the Sun in No. D. H. M. D. H. M. D. H. M.
4500 227500
3818 1,828,911,000,00 232,577,115,137,000,000 days hours 1

18 35

21 19 5 21
Mercury

6.5
Unkn. 95000 Unkn.

21,236,804

9,195,534,500 15 13 2 3 13 19 2 17 40 8 17 1 1 Unkn. 690001

43
691,351,300
258,507,832,200 39 17 3 7 3

4 12 25 10 23 4
Earth 1
1 58000 1042

199,859,860

265,404,598,080 64 10 4 19 18 50 15 22 41 12 11 5
Moon 13+
.43 2290 95

14,898,750
5,408,246,000 64 10 5

79 7 48 31 1 Mars

Unkn. 47000! 556 62,088,40

45,969,335,840, 121 .43

0

1 8 53

107 16 Jupiter

220 .036 25000/25920 20,603,970,000 278,153,595,000,000 290 0

0 22 37 Saturn

94 .011 18000/20493 14,102,562,000

155,128,182,000,000 767 Georgian! .0029

The Moon belonging to the Earth goes round its 18 7000 Unkn.

3,678,183,000 20,976,679,225,000 1307 0

orbit in 27 days, 7 hours, 43 minutes. U Since the year 1800, there have been discovered three very small celestial bodies, revolving round the Sun, in elliptical orbits, of considerable eccentricity, situate between the orbits of Mars and of Jupiter. Dr. Herschell has given them the general appellation of asteroids. They have been particu. Jarly designated by the mythological names of Ceres, Pallas, and Juno; but M. de la Lande, with more justice and reason, chooses to name them after their first discoverers-Piazzi, Olbers, and Harding. A fourth, it is said, bas been lately discovered, also, between the orbits of Mar’s and Jupiter.

Moons. 2

SUN

25

Venus

49

40

[graphic]

CHAP. III.

The COPERNICAN SYSTEM demonstrated to

be true.

M

Of matter
and mo. 99.

ATTER is of itself inactive, and indif. tion.

ferent to motion or rest. A body at rest can never put itself in motion; a body in motion can never stop or move slower of itself. Hence, when we see a body in motion, we conclude that some other substance must have given it that motion; when we see a body fall from motion to rest we conclude that has some other body or cause stopt it.

100. All motion is naturally rectilineal. A bullet thrown by the hand, or discharged from a cannon, would continue to move in the same direction it received at first, if no other power diverted its course. Therefore, when we see a body moving in a curve of whatever kind, we conclude it must be acted upon by two powers at least : one to put it in motion, and another drawing it off from the rectilineal course which it would otherwise have continued to move

in. Gravity 101. The power by which bodies fall toward the demon.

Earth, is called gravity or attraction. By this power in the Earth it is, that all bodies on whatever side, fall in lines perpendicular to its surface. On opposite parts -of the Earth, bodies fall in opposite directions ;-—all toward the centre, where the whole force of gravity is, as it were, accumulated. By this power constantly acting on bodies near the Earth, they are kept from leaving it altogether ; and those on its surface are kept there on all sides, so that they cannot fall from it. Bodies thrown with any obliquity are drawn, by this power, from a straight line into a curve, until they fall to the ground: the greater the force by which they are thrown, the greater is the distance they are carried before they fall. If we suppose a body carried se

strable.

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