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INDEX.

The numeral Figures refer to the Pages, and the
small n to the Notes subjoined.

A.

ACCELERATION of the stars, 160.

Eras or epochs, 421.`

Angle, under which an object appears, what, 128, n.
Annual parallax of the stars, 138.

Anomaly, what, 176.

Ancients, their superstitious notions of eclipses, 303.

Their method of dividing the zodiac, 381.

Antipodes, what, 86.

Apsides, line of, 176.

ARCHIMEDES, his ideal problem for moving the Earth, 112.
Areas, described by the planets, proportional to the times,
109.

Astronomy, the great advantages arising from it both in our
religious and civil concerns, 31.

Discovers the laws by which the planets move, and are
retained in their orbits, 31.

Atmosphere, the higher the thinner, 121.

Its prodigious expansion, 121.

Its whole weight on the Earth, 122.

Generally thought to be heaviest when it is lightest, 123.
Without it, the heavens would appear dark in the day-time,

123.

Is the cause of twilight, 124.

Its height, 124.

Refracts the Sun's rays, 124.

Causeth the Sun and Moon to appear above the horizon
when they are really below it, 124.

Foggy, deceives us, in the bulk and distance of objects,

129.

Attraction, 76.

Decreases as the square of the distance increases, 76.
Greater in the larger than in the smaller planets, 112.
Greater in the Sun, than in all the planets if put together,

112.

Axes of the planets, what, 38.

Their different positions with respect to one another,

83.

Axis of the Earth, its parallelism, 145.

Its position variable as seen from the Sun or Moon, 308.
The phenomena, thence arising, 310.

B.

Bodies, on the Earth, lose of their weight the nearer they
are to the equator, 82.

How they might lose all their weight, 83.

How they become visible, 117.

C.

Calculator (an instrument) described, 437.

Calendar, how to inscribe the Golden numbers right in it
for shewing the days of new Moons, 396.

Cannon-ball, its swiftness, 68.

In what times it would fly from the Sun to the different
planets and fixed stars, 68.

CASSINI, his account of a double star eclipsed by the Moon,

53.

His diagrams of the paths of the planets, 98.

Catalogue of the eclipses, 282.

Of the constellations and stars, 382.

Of remarkable æras and events, 421.

Celestial globe improved, 447.

Centripetal and centrifugal forces, how they alternately over
come each other in the motions of the planets, 108, 110.
Changes in the heavens, 385.

Circles, of perpetual apparition and occultation, 91.
Of the sphere, 140.

Contain 360 degrees whether they be great or small, 152.
Civil year, what, 309.

COLUMBUS (CHRISTOPHER) his story concerning an eclipse,

303.

Clocks and watches, an easy method of knowing whether they
go true or false, 164.

Why they seldom agree with the Sun if they go true,

168-181.

How to regulate them by equation-tables and a meridian-
line, 166.

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Constellations, ancient, their number, 380.

The number of stars in each, according to different as

tronomers, 382.

Cycle, solar, lunar, and Roman, 395.

D.

Darkness at our SAVIOUR'S crucifixion supernatural, 317-

416.

Day, natural and artificial, what, 394.

And night, always equally long at the equator, 90.

Natural, not completed in an absolute turn of the Earth
on its axis, 164.

Degree, what, 152.
Digit, what, 306, n.

Direction, (number of), 412.

Distances of the planets from the Sun, an idea of them, 68.
A table of them, 73.

How found, 132; and in the Dissertation on the transit of
Venus, chap. XXIII.

Diurnal and annual motions of the earth illustrated, 141-
145.

Dominical letter, 413.

Double projectile force, a balance to a quadruple power of
gravity, 109.

Double star covered by the Moon, 52.

E.

Earth, its bulk but a point as seen from the Sun, 32.

Its diameter, annual period, and distance from the Sun,

49.

Turns round its axis, 49.

Velocity of its equatorial parts, 49.

Velocity in its annual orbit, 49.

Inclination of its axis, 49.

Proof of its being globular, or nearly so, 50, 261.
Measurement of its surface, 50.

Difference between its equatorial and polar diameters, 59.
Its motion round the Sun demonstrated by gravity,

77, 78, by Dr. BRADLEY'S observations, 80, by the
eclipses of Jupiter's satellites, 158.

Its diurnal motion highly probable from the absurdity that
must follow upon supposing it not to move, 78, 86, and
demonstrable from its figure, 87, this motion cannot be
felt, 83.

Objections against its motion answered, 80, 85.

It has no such thing as an upper or an under side, 86. in
what case it might, 87.

The swiftness of its motion in its orbit compared with
the velocity of light, 139.

Its diurnal and annual motions illustrated by an easy ex-
periment, 141.

Proved to be less than the Sun, and bigger than the Moon,

262.

Easter cycle, 412.

Eclipsareon (an instrument) described, 458.

Eclipses of Jupiter's satellites, how the longitude is found
by them, 154, they demonstrate the velocity of light,

156.

Of the Sun and Moon, 261-316,

Why they happen not in every month, 263.

When they must be, 263.

Their limits, 264.

Their period, 268.

A Dissertation on their progress, 268.

A large catalogue of them, 282.

Historical ones, 301.

More of the Sun than of the Moon, and why, 303.

The proper elements for their calculation and projection,

$18.

Ecliptic, its signs, their names and characters, 68.

Makes different angles with the horizon every hour and
minute, 234, how these angles may be estimated by the
position of the Moon's horns, 220.

Its obliquity to the equator less now than it was formerly,

388.

Elongations, of the planets, as seen by an observer at rest on
the outside of all their orbits, 94.

Of Mercury and Venus, as seen from the Earth, illus-
trated, 102, its quantity, 102.

Of Mercury, Venus, the Earth, Mars, and Jupiter; their
quantities, as seen from Saturn, 105.

Equation of time, 165-181,

Equator, day and night always equal there, 90.

Makes always the same angle with the horizon of the
same place; the ecliptic not, 234.

Equinoctial points in the heavens, their precession, 181, a
very different thing from the recession or anticipation
of the equinoxes on the Earth, the one no ways occa
sioned by the other, 185.

Eccentricities of the planets' orbits, 110.

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