God's glory in the heavens/Synoptical Tables

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God's glory in the heavens (1867)
by William Leitch

Synoptical Tables

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2892310God's glory in the heavens — Synoptical Tables1867William Leitch

SYNOPTICAL TABLES.

N.B.— The epoch for the elements in the following tables is, unless otherwise stated, the beginning of the present century.

THE SOLAR SYSTEM.

LAWS OF MOTION.

1. Every body continues in a state of rest or uniform rectilineal motion, unless affected by some mechanical force.

2. Every change of motion is proportionate to the force impressed, and is made in the direction of that force.

3. Action must always be equal and contrary to reaction, or the actions of two bodies on each other are always equal and directed to contrary sides.

KEPLER'S LAWS.

1. The orbit of each planet is an ellipse, of which the sun occupies one of the foci.

2. The areas described about the sun by the radius vector of the planet are proportional to the times employed in describing them.

3. The squares of the times of the sidereal revolutions of the planets are to each other as the cubes of their mean distances from the sun.

LAW OF GRAVITATION.

Any two bodies attract each other with a force proportional directly to the quantity of matter they contain, and inversely to the square of their distances.

ELEMENTS OF ELLIPTICAL MOTION.

1. The mean distance of the planet from the sun, or half the major axis of the orbit.

2. The duration of a mean sidereal revolution of a planet.

3. The mean longitude of the planet at a given epoch.

4. The longitude of the perihelion at a given epoch.

5. The inclination of the orbit to the ecliptic at a given epoch.

6. The longitude of the nodes at a given epoch.

7. The eccentricity of the orbit.

SECULAR VARIATIONS IN ORBIT.

The position of the apsides.

The inclination of the orbit to the ecliptic.

The position of the nodes.

The amount of eccentricity.

NUMBER OF BODIES OF SOLAR SYSTEM.

Principal planets, including Vulcan,	9
Asteroids, (1861,)	71
Satellites,	18
Periodic comets,	27
Planetary rings,	3
Zones of asteroids, probably	3

LAWS OF LIGHT.

Intensity inversely proportional to the square of the distance from source.
Velocity in miles, per second,	192,000

BODE'S LAW OF PLANETARY DISTANCES.

The intervals between the orbit of Mercury and the other planetary orbits go on doubling as we recede from the sun.

The first of the following series represents the distances from the orbit of Mercury; the second, by adding 4 as the distance of Mercury from the Sun, represents the planetary distances from the centre of the system:—

	Mer.	Ven.	Earth.	Mars.	Ast.	Jup.	Sat.	Uran.	Nep.
Distance from Mercury,	0.0	3.0	6.0	12.0	24.0	48.0	96.0	192.0	384.0
	4.0	4.0	4.0	4.0	4.0	4.0	4.0	4.0	4.0
	—	—	—	—	—	—	——	——	——
Distance from Sun,	4.0	7.0	10.0	16.0	28.0	52.0	100.0	196.0	388.0
Actual distances.	3.9	7.3	10.0	15.2	27.4	52.0	95.4	192.0	300.0

EXTERIOR AND INTERIOR PLANETS.
Average density of planets exterior to asteroids (water =1),	1.07
Average density of interior planets,	5.33
Proportion of average diameter of interior planets to that of exterior,	1-10th
Average rotation of exterior planets, in hours, nearly	10
Average rotation of~~— — —~~ interior planets, nearly	24
Number of satellites of exterior planets,	18
Number of satellites of~~— — —~~ \|interior planets,	1

KIRKWOOD'S LAW.

The square of the number of times that each planet rotates during one revolution in its orbit is proportional to the cube of the diameter of its sphere of attraction.

The sphere of attraction is that within which the attraction of one planet is greater than that of the next interior or exterior planet.

PLANETARY ELEMENTS.
Name of Body.	Volume.	Density.	Light and Heat.	Gravity.	Time of Rotation.		Distance from Sun.
					h.	m.
Sun	1415225	.250	...	28.36	607	48	...
Vulcan	.0035	...	30.32	...	...		.19
Mercury	.0595	1.225	7.58	0.48	24	6	.39
Venus	.9960	.908	1.91	0.9	23	21	.73
Earth	1.0	1.0	1.0	1.0	23	56	1.00
Mars	.1364	.972	0.43	0.49	24	37	1.52
Asteroids	...	...	...	...	...		2.74
Jupiter	1491.0	.227	.0372	2.45	9	55	5.20
Saturn	772.0	.131	.0111	1.09	10	29	9.54
Uranus	86.5	.167	.0026	0.76	...		19.18
Neptune	76.6	.321	.0011	1.36	...		30.03

THE SUN
Volume (Earth's = 1),	1,415,225
Mass (Earth's = 1),	354,936
Density (Earth's = 1),	0.2543
Diameter (Earth's = 1),	111.454
Diameter~~— — —~~ in miles,	882,646
Diameter~~— — —~~apparent, mean,	32′ 12″.6
Gravity at equator (Earth's = 1),	28
In one second of time bodies fall, in feet,	335
Period of rotation in days,	25.5
Zone of maximum spots north from the equator,	11°—15°
Usual limit of spots from the equator,	33°
Period of maximum number of spots, in years,	10
Diameter of maximum spot (Sun's = 1),	0.05
Breadth of zone of drift, at equator, direction of rotation,	30°
Breadth of zone of drift,„ in each hemisphere, opposite direction,	30°
Light of the Sun (light of star of 1st Mag. = 1),	108,000,000,000
Intensity of Sun's light (electric light = 1),	4
Intensity of Sun's light~~— — —~~ : (wax candle = 1),	15,000
Heat of each square foot of surface, mechanical effect, in horse-power,	7,000
Heat of each square foot of surface, equal the combustion of cwts. of coals per hour,	13.5
Heat of each square foot of surface, equal 5 lbs. matter falling with velocity per second, in miles,	390
Heat at centre of disc (heat at border = 1),	2
Diameter of largest spots, in miles,	50,000
Number of strata in atmosphere,	4
Spots seen to rotate on their axis (in days), about	18
Heat equivalent to loss of mechanical force by Mercury falling into Sun (a year's heat of Sun = 1),	3
Velocity of bodies near the Sun (miles per second), about	400
Point in Hercules to which the Sun is advancing, declination 35° N., right ascension,	250°
Velocity of Sun in its orbits, miles per year,	150,000,000
Mean distance from the earth in miles,	95,000,000
Mean distance from the earth in miles,~~— — —~~ (Earth's radius = 1),	23,984
Light of Sun reaches the Earth in	8^m
Inclination of axis to ecliptic,	82° 40′ 0″
Time of passing over one degree of mean longitude,	24^h 20^m 58^s
Eccentricity of orbit (semi-axis major = 1),	.01685
Mean longitude,	280° 34′ 10″
Longitude of the perigee,	270° 30′ 5″
Greatest equation of centre,	1° 55′ 27″
Motion of perigee in a year,	1′ 1″

MERCURY.
Volume (Earth's = 1),	0.06
Mass (Earth's = 1),	0.0769
Density (Earth's = 1),	1.225
Diameter (Earth's = 1),	0.389
in miles,~~— — —~~	3,200
Diameter~~— — —~~ apparent mean,	6″.9
Gravity (Earth's = 1),	0.48
In one second of time bodies fall, in feet,	7.07
Period of rotation,	24^h. 5^m. 28^s.
Light and heat received at perihelion (Earth's =1),	10.58
Light and heat received„ at aphelion,	4.59
Light and heat received„ at mean distance.	7.58
Least elongation from Sun,	16° 12′
Greatest elongation.	28° 48′
Height of mountain at southern horn in miles.	12
Height of same (radius of Mercury = 1),	.008
Mean distance from the Sun in miles,	36,725,000
Mean distance from the sun~~— — —~~ (Earth's distance =1	.3870084
Greatest distance (Earth's distance = 1),	.40666927
Least distance (Earth's distance = 1),	.3075041
Eccentricity (semi-major axis = 1),	.2056178
Sidereal revolution in days,	87.9692824
Synodical revoultion in days,	115.877
Longitude of perihelion,	74° 57′ 21″
Longitude of ascending node,	46° 23′ 55″
Inclination of orbit to ecliptic,	7° 0′ 13″
Mean daily motion in orbit,	2° 11′ 23″
Mean daily motion in orbit,~~— — —~~ miles per hour,	109,360
Inclination of bands to the planet's orbit,	70°
Days in falling to the Sun,	15.6

VENUS.
Volume (Earth's = 1),	0.996
Mass (Earth's = 1),	0.908
Density (Earth's = 1),	0.923
Diameter (Earth's = 1),	0.975
Diameter~~— — —~~ in miles,	7700
{{ditto bar\|Apparent, mean,	16″.9
Gravity (Earth's = 1),	0.98
In one second of time bodies fall, in feet,	14.5
Period of rotation,	23^h. 21^m. 7^s.
Light and heat (Earth's = 1),	1.91
Least elongation,	45°
Greatest elongation.	47° 12′
Greatest height of mountains in miles.	27
Mean distance from the Sun in miles,	68,000,000
Mean distance from the Sun~~— — —~~ (Earth's = 1),	0.7233316
Eccentricity (semi-major axis = 1),	0.00686074
Sidereal revolution in days.	224^d. 6^h. 49^m. 8^s.
Mean synodical revolution in days,	583.920
Longitude of perihelion.	128° 43′ 53″
Longitude of ascending node.	74° 54′ 12″
Inclination of orbit to ecliptic,	3° 23′ 28″
Mean daily motion in orbit,	1° 36′ 7″
Mean daily motion in orbit,~~— — —~~ miles per hour	80,000
Inclination of axis to ecliptic.	Uncertain
Next transit of Venus on December 8, 1874.
Days in falling to the Sun,	39.7

THE EARTH.
Volume,	1.000
Mass (Sun's = 1),	0.0000028173
Density (water = 1),	5.6747
Diameter, mean, in miles,	7916
Diameter~~— — —~~ polar, in miles,	7898
Diameter~~— — —~~ equatorial, in miles,	7924
Circumference in miles,	25,000
In one second of time bodies fall, latitude of London, in feet,	16.835
Centrifugal force at equator (gravity = 1),	0.00346
Times rotation requires to be increased to neutralise gravity at equator,	17
Period of rotation in sidereal hours,	24
Length of a mean solar day in sidereal time,	24^h. 3^m.- 56^s..55
Length of a~~— — —~~ sidereal day in mean solar time,	23^h. 56^m. 4^s.09
Daily acceleration of sidereal time in mean solar time,	3^m. 55^s..09
Greatest difference between the mean and apparent solar time,	16^m. 16^s.
Greatest height of mountains in miles,	5
Axis of the poles (axis of diameter of equator = 305),	304
Greatest depth of ocean in miles,	9
Mean distance from the Sun (Earth's radius = 1),	23,984
Mean distance from the Sun~~— — —~~ in miles,	95,000,000
Distance at perihelion (mean distance = 1),	.9832
distance at~~— — —~~ aphelion (mean distance = 1), .	1.0168
Eccentricity (semi-major axis = 1),	0.016783568
Sidereal revolution in mean solar days.	365^d. 6^h. 9^m. 9^s..6
Anomalistic revolution in mean solar days.	365^d. 6^h. 13^m. 49^s.
Tropical revolution in mean solar days,	365^d. 5^h. 48^m. 49^s..7
Interval between vernal and autumnal equinoxes,	186^d. 11^h. 34^m.
Interval between autumnal and vernal equinoxes,	178^d. 18^h. 7^m.
The latter shorter than the former, by	7^d. 17^h. 27^s.
Time required by Sun's light to reach the Earth,	8^m. 13^s..3
Constant of aberration,	20″.36
Average horizontal refraction,	33′ 6
Average refraction at 45° of altitude,	57″
Height of atmosphere in miles,	40
Height of atmosphere, supposing no decrease of density,	5
Greatest height at which clouds exist, in miles,	10
Distance to which a body must be projected horizontally to revolve as a satellite, in miles,	4.35
Action of the Moon on the tides (Sun's = 1),	3
Daily mean retardation of high-water,	50^m. 28^s.
Mean retardation in syzygies,	39^m. 12^s.
Mean retardation in quadratures,	1^h. 14^n. 58^s.
Revolution of the Sun's perigee in mean solar days,	7,645,793
Mean longitude of perigee,	100° 30′10″
Earth's motion in perihelion in a mean solar day,	1° 1′ 9″
Mean motion in a mean solar day,	59′ 8″.33
Mean Motion~~— — —~~ in a sidereal day,	59′ 58″.64
Motion in aphelion in a mean solar day,	57′ 11″.50
Mean longitude of perihelion,	90° 30′ 5″
Annual motion of perihelion,	11″.8
Same referred to the ecliptic,	1° l″.9
Tropical revolution of perihelion in mean solar years,	20,984
Obliquity of the ecliptic,	23° 27′ 56″.5
Annual diminution of obliquity,	0″.457
Limit of variation,	2° 42′
Nutation lunar, semi-axis major of the ellipse,	9″.4
Nutation~~— — —~~ solar, maximum,	0″.493
Luni-solar precession of the equinoxes, annual,	50″.41
Planetary precession,	0″.31
General precession,	50″.11
Complete revolution of the equinoxes in years,	25,868
Lunar nutation in longitude,	17″.579
Solar nutation in longitude,	1″.137
Rate per minute at which equator rotates, in miles,	17
Rate per second of her velocity in orbit, in miles,	20
Days in falling to the Sun,	64.6

THE MOON.
Volume (Earth's = 1),	1-49th
Mass (Earth's = 1), .	1-80th
Density (Earth's = 1),	0.615
Density~~— — —~~ (water = 1),	3.37
Diameter (Earth's = 1),	0.264
Diameter~~— — —~~ in miles,	2164.6
Diameter~~— — —~~ apparent, mean,	31′ 7″
Diameter apparent~~— — —~~ minimum,	29′ 21″.9
Diameter~~— — —~~ maximum.	33' 3″.1
Gravity at surface (Earth's = 1),	1-6th
In one second of time bodies fall, in feet.	2-6
Centre of figure nearer the earth than centre of gravity, in miles,	33
Elevation of highest mountain in the Moon (Doerfel), in feet,	24,945
Elevation of highest mountain~~— — —~~ (Moon's diam. = 1),	1-454th
Elevation of highest mountain~~— — —~~ on the Earth, in feet,	28,180
Elevation of highest mountain~~— — —~~(Earth's diam. = 1)	1-1480th
Greatest depth of craters below the general surface in feet,	17,000
Greatest diameter of craters, or cavities with or without raised walls, in miles,	55
Greatest diameter„ of walled plains, in miles,	150
Greatest height of central cone, in feet.	5000
Longest bright ray (Tycho),	1800
Rills, greatest length in miles,	150
Rills~~— — —~~ greatest breadth in feet,	6000
Rills~~— — —~~ number,	90
Number of mountains higner than Mont Blanc,	28
Length of the range of the Lunar Appenines, in miles,	200
Proportion of surface covered with craters,	3-5ths
Tycho, height in feet,	20,180
Tycho~~— — —~~ diameter in miles,	54
Tycho~~— — —~~ longest ray,	1800
Tycho~~— — —~~ number of bright rays, about	54
Diameter of Mt. Vesuvius in feet,	500
Height of Pico, a bright isolated peak, in feet,	7060
Disc of the Earth, as seen from Moon (Moon's disc = 1),	14
Proportion of the Moon's surface alternately hid and visible,	1-7th
Light of the Moon at mean distance (Sun's = 1) .	1-800000th
Heat of the Moon (heat of a candle at distance of 15 feet = 1),	1-3d
Velocity of projection necessary for a lunar body to reach the Earth, feet, per second.	8200
Distance in miles of Moon's surface under a magnifying power of 1000,	240
A circle of one second in diameter as seen from the Earth, in square miles.	1
Limit of vision in the case of a circle or square,	60″
Limits of vision in an indefinitely extended object,	6″
Magnifying power required to see an embankment, 6 feet broad,	6000
Highest power attained with distinct vision,	2000
Maximum limit of atmosphere (one inch of mercury = 1),	1-45th
Maximum limit of~~— — —~~ refraction (at surface of earth = 1),	1-1980th
Maximum limit of~~— — —~~ horizontal refraction at Moon,	1"
Eclipses, annual number, minimum (only solar),	2
Eclipses, annual number.~~— — —~~ maximum,	7
Eclipses,~~— — —~~ maximum of annular phase,	12^m. 24^s.
Eclipses,~~— — —~~ totality (solar),	7^m. 58^s.
Eclipses, length of Earth's shadow (distance of moon = 1),	3.5
Eclipses,~~— — —~~ period of recurrence in same order and magnitude in years,	18-6
Eclipses,~~— — —~~ total number in period (29 lunar, 41 solar), about	70
Mean distance from the Earth (Earth's radius = 1),	60.2734
Mean distance from the Earth~~— — —~~ in miles	237,000
Period, in days, of rotation,	27.3215824
Period, in days,~~— — —~~ revolution, mean tropical,	27.3215824
Period, in days, revolution,~~— — —~~ mean sidereal,	27.321661
Period, in days, revolution,~~— — —~~ mean synodical,	29.530588
Period, in days, revolution,~~— — —~~ mean anomalistic,	27^h. 18^m. 37^s.
Period, in days,~~— — —~~ mean revolution of node,	6793.39108
Period, in days, mean revolution of~~— — —~~ apsides.	3232.575343
Motion eastwards of line of apsides in each lunation.	3°
Mean longitude of Moon,	118° 17′ 8″
Mean longitude~~— — —~~ node,	13° 53′ 17″.7
Mean longitude~~— — —~~ perigee	266° 10′ 7″.5
Mean inclination of orbit to ecliptic,	5° 8′ 47″.9
Mean inclination~~— — —~~ maximum variation.	5° 8′ 47″.1
Eccentricity of orbit (semi-axis major = 1),	0.0549080
Inclination of axis to ecliptic,	1° 30′ 10″.8
Mean motion in a solar day,	13° 10′ 35″
Maximum variation,	35′ 42″
Maximum~~— — —~~ annual equation,	11′ 11″.97
Maximum~~— — —~~ equation of centre,	6° 17′ 12″
Horizontal parallax, maximum,	1° 1′ 24″
Horizontal parallax~~— — —~~ mean,	57′ 0″.9
Horizontal parallax~~— — —~~ minimum,	53′ 48″

MARS.
Volume (Earth's = 1),	0.1364
Mass (Earth's = 1),	0.1324
Density (Earth's = 1),	0.972
Diameter (Earth's = 1),	0.519
Diameter~~— — —~~ in miles,	4070
Diameter~~— — —~~, apparent, mean,	5″.8
Diameter, apparent,~~— — —~~ minimum,	3″.3
Diameter, apparent,~~— — —~~ maximum.	23″-5
Gravity (Earth's = 1),	0.49
In one second of time bodies fall, in feet,	7.9
Time of rotation on axis,	24^h. 37^m. 22^s.
Revolution, sidereal, in days,	686.97945
Revolution,~~— — —~~ synodical.	779.836
Light and heat from Sun (Earth's = 1),	0.43
Polar less than equatorial diameter.	1-16th
Distance from the Sun, mean, in miles,	145,750,000
Distance from the Sun,~~— — —~~ mean, (Earth's = 1),	1.523691
Distance from the Sun,~~— — —~~maximum,	1.665779
Distance from the Sun,~~— — —~~minimum.	1.381602
Eccentricity of orbit (semi-axis major = 1)	0.93258
Eccentricity of orbit~~— — —~~, annual increase,	0.00000090176
Longitude of perihelion,	332° 23′ 56″.6
Longitude~~— — —~~ annual increase,	15″-8
Longitude~~— — —~~ ascending node.	48° 0′ 3″-5
Inclination of orbit to ecliptic,	2″-8
Inclination of orbit to ecliptic,~~— — —~~ annual decrease.	0″.014
Mean daily motion in orbit.	31′ 26″-7
Inclination of axis to the ecliptic,	59° 41′ 49″
Greatest arc of retrogradation,	19° 35′
Edge of south polar spot from pole in winter,	35°
Edge of south polar spot from pole~~— — —~~ in summer.	5°
Brightness of polar spots (mean brightness = 1),	2

ASTEROIDS.
Name.		Length of Sidereal Revolution in Days.	Inclination of Orbit to Ecliptic.			Discoverer.	Year of Discovery.
			°	′	″
1.	Ceres	1681.271	10	36	30.9	Piazzi	1801
2.	Pallas	1686.089	34	37	20.0	Olbers	1802
3.	Juno	1592.736	13	3	17.0	Harding	1804
4.	Vesta	1325.669	7	8	25.0	Olbers	1807
5.	Astrsea	1511.369	5	19	23.0	Hencke	1845
6.	Hebe	1379.635	14	46	32.0	Hencke	1847
7.	Iris	1345.600	5	28	16.0	Hind	1847
8.	Flora	1193.281	5	53	3.0	Hind	1847
9.	Metis	1346.940	5	35	55.0	Graham	1848
10.	Hygeia	2043.386	3	47	11.0	De Gasparis	1849
11.	Parthenope	1399.074	4	36	54.0	De Gasparis	1850
12.	Victoria	1303.255	8	23	7.0	Hind	1850
13.	Egeria	1515.850	16	33	7.0	De Gasparis	1850
14.	Irene	1515.373	9	5	33.0	Hind	1851
15.	Eunomia	1576.493	11	43	50.0	De Gasparis	1851
16.	Psyche	1834.658	3	3	37.0	De Gasparis	1852
17.	Thetis	1441.859	5	35	39.0	Luther	1852
18.	Melpomene	1270.498	10	10	38.0	Hind	1852
19.	Fortuna	1397.192	1	33	18.0	Hind	1852
20.	Massilia	1365.095	0	41	5.0	De Gasparis	1852
21.	Lutetia	1542.318	3	5	6.0	Goldschmidt	1852
22.	Calliope	1814.762	13	44	39.0	Hind	1852
23.	Thalia	1554.131	10	13	59.0	Hind	1852
24.	Themis	2051.993	0	49	24.0	De Gasparis	1853
25.	Phocea	1350.281	21	42	30.0	Chacornac	1853
26.	Proserpine	1580.714	5	0	26.0	Luther	1853
27.	Euterpe	1332.301	1	39	42.0	Hind	1853
28.	Bellena	1700.541	9	31	21.0	Luther	1854
29.	Amphitrite	1499l.309	6	8	20.0	Chacornac	1854
30.	Urania	1332.083	2	10	9.0	Hind	1854
31.	Euphrosene	2083.297	26	53	26.0	Fergusson	1854
32.	Pomona	1516.367	5	29	14.0	Goldschmidt	1854
33.	Polyhymnia	1770.912	1	56	48.0	Chacornac	1854
34.	Circe	1606.575	5	26	55.0	Chacornac	1855
35.	Leucothia	1873.018	8	15	18.0	Luther	1855
36.	Atalanta	1665.965	18	42	9.0	Goldschmidt	1855
37.	Fides	1568.671	3	7	10.0	Luther	1855
38.	Leda	1656.340	6	58	32.0	Chacornac	1856
39.	Lsetitia	1683.348	10	20	51.0	Chacornac	1856
40.	Harmonia	1246.846	4	15	48.0	Goldschmidt	1856
41.	Daphne	1358.34	15	48	23.0	Goldschmidt	1856
42.	Isis	1386.914	8	34	40.0	Pogson	1856
43.	Ariadne	1191.108	3	20	0.0	Pogson	1857
44.	Nysa	1599.700	3	53	0.0	Goldschmidt	1857
45.	Eugenia	1617.641	6	35	0.0	Goldschmidt	1857
46.	Hestia	1406.614	2	18	0.0	Pogson	1857
47.	Aglaia	1793.933	5	6	0.0	Luther	1857
48.	Doris	2000.220	6	30	0.0	Goldschmidt	1857
49.	Pales	1980.255	3	8	0.0	Goldschmidt	1857
50.	Virginia	1596.140	2	52	0.0	Fergusson	1857
51.	Nemausa	...	9	36	38.0	Laurent	1857
52.	Europa	...	7	24	41.0	Goldschmidt	1858
53.	Calypso	...	5	6	59.0	Luther	1858
54.	Alexandra	...	11	47	9.0	Goldschmidt	1858
55.	Pandora	...	7	13	30.0	Searle	1858
56.	Pseudo Daphne	...	7	56	2.0	Schubert	1858
57.	Mnemosyne	...	15	7	40.0	Luther	1859
58.	Concordia	...	...			Luther	1860
59.	(Not named)	...	...			Chacornac	1860
60.	Titania	...	4	40	18.0	Fergusson	1860
61.	Danae	...	...			Goldschmidt	1860
62.	Erato	...	2	14	15.0	Forsten	1860
63.	Ansonia	...	...			De Gasparis	1860
64.	Angelina	...	...			Tempel	1861
65.	Maximiliana	...	...			Tempel	1861
66.	Maia	...	...			Tuttle	1861
67.	Asia	...	...			Pogson	1861
68.	Leto	...	...			Luther	1861
69.	Hesperia	...	...			Schiaparelli	1861
70.	Ponopea	...	...			Goldschmidt	1861
71.	Niobe	...	...			Luther	1861

Aggregate mass (Earth's = 1), less than	1-4th
Inclination of orbit to ecliptic, greatest (Pallas),	34° 37′ 20″
Inclination of orbit to ecliptic,~~— — —~~ least (Massilia),	0° 41′ 5″
Distance from Sun (Earth's = 1), greatest (Euphrosene)	3.192282
{{{1}}}~~— — —~~ least (Ariadne),	2.19904
Distance, supposed planet, according to Bode's law,	2.8
Pallas, diameter in miles,	672
Pallas~~— — —~~ surface (Earth's =1),	1-40th
Pallas~~— — —~~ supposed density (Earth's = 1),	1
Pallas~~— — —~~ gravity (Earth's =1),	1-12th
Pallas~~— — —~~ length of seconds' pendulum, in inches,	3
Magnitudes through which some vary on successive nights,	9-12th
Supposed disrupted planet, according to Kirkwood's, law, diameter in miles,	5000
Supposed disrupted planet,~~— — —~~ period of rotation, in hours,	57.5

JUPITER.
Volume (Earth's = 1),	1491
Mass (Earth's = 1),	338.718
Density (Earth's = 1),	.227
Diameter (Earth's = 1),	11.225
Diameter~~— — —~~ in miles,	92.164
Diameter~~— — —~~ apparent, mean,	38″.4
Diameter apparent,~~— — —~~ minimum,	30″
Diameter apparent,~~— — —~~ maximum,	46″
Gravity (Earth's = 1),	2.45
Gravity„ feet fallen in one second of time,	39.4
Rotation on axis,	9^h. 55^m. 50^s.
Light and heat from Sun at perihelion (Earth's = 1),	.0408
Light and heat from Sun at„ aphelion,	.0336
Light and heat from Sun at„ mean distance,	.0372
Polar less than equatorial diameter,	1-20th
Polar less than equatorial diameter, ~~— — —~~ if planet were equally dense throughout,	1-10th
Magnifying power required to see the belts~~— — —~~	30
Magnifying power required to see the belts~~— — —~~ well,	300
Greatest number of belts observed,	40
Number of permanent belts,	2
Time Cassini's spot was seen at intervals, in years,	43
Proper motion in longitude, for one revolution, of some spots,	3°
Velocity of the wind from slower moving spots, feet in a second,	350
Velocity of wind in greatest hurricane on the earth, feet in a second,	50
Distance, east and west, of centre of disc beyond which spots are not usually visible,	1^h. 27^m.
Proportion of brightness at poles to that of the equator,	1-2d
Distance from the Sun, mean, in miles, (Earth's = 1),	494,256,000
Distance from the Sun,~~— — —~~ maximum	5.202767
Distance from the Sun,~~— — —~~ minimum,	5.453663
Eccentricity of orbit (semi-axis major = 1),	4.951871
Eccentricity of orbit~~— — —~~ annual increase.	.0482235
Longitude of perihelion,	.000001593
Longitude of perihelion,~~— — —~~ annual increase.	11° 8′ 35″
Longitude of perihelion,~~— — —~~ ascending node,	6″.96
Longitude of perihelion,~~— — —~~ annual decrease.	98° 26′ 19″
Longitude of perihelion,~~— — —~~\|annual decrease,	34″.3
Inclination of orbit to ecliptic,	1° 18′ 51″
Inclination of orbit to ecliptic,~~— — —~~ annual decrease,	0″-226
Motion, mean daily,	4′ 59″
Motion,~~— — —~~ in 365 days,	30° 20′ 32″
Inclination of axis to ecliptic.	3° 5′ 30″
Mean arc of retrogradation.	9° 54′
Revolution, sidereal, in mean solar days,	4332.584821
Revolution,~~— — —~~ synodical,	398.867

JUPITER'S SATELLITES.
No.	Sidereal Revolution.				Distance. Jupiter's radius = 1.	Orbit inclined to Jupiter's equator.			Diameter in miles.	Mass. Jupiter =1	Apparent Diameter from Jupiter.
	d.	h.	m.	s.		°	′	″			′	″
1	1	18	27	23	6.048	0	0	7	2436	.000017	31	11
2	3	13	13	42	9.623	0	1	6	2187	.000023	17	35
3	7	3	42	33	15.350	0	5	3	3573	.000088	18	0
4	16	16	32	11	26.998	0	0	24	3057	.000043	8	46

^[1] (Mean longitude of the 1st + twice mean longitude of 3d) 3 times mean longitude of 2d is always = ,

180°

↑ In consequence of this remarkable relation, the 1st, 2d, and 3d satellites can never be eclipsed all at once.

SATURN.
Volume (Earth's = 1),	772
Mass (Earth's = 1), .	101.364
Density (Earth's = 1),	.131
Diameter (Earth's = 1),	9.022
Diameter~~— — —~~ in miles,	75.070
Diameter~~— — —~~ apparent, mean,	17″.1
Diameter apparent~~— — —~~ minimum.	15″.0
Diameter apparent~~— — —~~ maximum.	20″.0
Gravity (Earth's = 1),	1.09
Gravity~~— — —~~ bodies fall in one second, in feet,	17.6
Light and heat from Sun, perihelion (Earth's = 1)	.0123
Light and heat from Sun~~— — —~~ aphelion,	.0099
Light and heat from Sun~~— — —~~ mean,	.0111
Polar less than equatorial diameter.	1-10th
Distance from the Sun, mean, in miles,	906,205,000
Distance from the Sun~~— — —~~, (Earth's = 1),	9,538,850
Distance from the Sun, in miles, ~~— — —~~ maximum,	10,073,270
Distance from the Sun, in miles, ~~— — —~~ minimum,	9,004,422
Eccentricity of orbit (semi-axis major = 1),	.0560265
Eccentricity of orbit, annual decrease,	.0312402
Longitude of perihelion,	89° 9′ 29″.8
Longitude of perihelion,~~— — —~~ annual increase,	19″.4
Longitude„ ascending node,	111° 56′ 37″.4
Longitude„ ascending node, annual decrease,	19″.4
Inclination of orbit to ecliptic,	2° 29′ 35″.7
Inclination of orbit to ecliptic,~~— — —~~ annual decrease,	0″.155
Motion, mean daily,	2′ 0″.6
Motion~~— — —~~, in 365 days,	12°13′36″.08
Inclination of axis to ecliptic,	31° 19′.0
Rotation on axis,	18^h. 29^m. 17^s.
Revolution, sidereal, in days,	10759.2197106
Revolution,~~— — —~~ synodical,	378.090
Mean arc of retrogradation,	6° 44′

SATURN'S RINGS.
Bright ring, exterior diameter in miles,	176,418
Bright ring,~~— — —~~ breadth of exterior division,	10,573
Bright ring,~~— — —~~ interval between the two divisions,	1,791
Bright ring,~~— — —~~ exterior diameter of interior division,	151,690
Bright ring,~~— — —~~ breadth of interior division,	17,175
Bright ring,~~— — —~~ time of rotation,	10^h, 35^m. 15^s.
Dusky ring, breadth,	6,350
Dusky ring„ interval between inner edge and Saturn,	7,460
Divisions, seen by Bond,	2
Divisions~~— — —~~ discovered by Bond in the year	1850
Years in which it will reach the planet by increase of breadth of system of rings (O. Striive),	125
Breadth of whole system of rings,	35,889
Exterior division of bright ring, exterior diameter,	40″.44
Exterior division~~— — —~~ new sub-division, exterior diameter (Encke),	37″.47
Exterior division~~— — —~~ new sub-division, interior diameter,	36″.04
Divisions of exterior bright ring, seen by Kater,	4
Divisions in inner bright ring, seen by De Vico,	2
Divisions in inner bright ring, seen by~~— — —~~ Dawes,	4
Isolated stationary bright spots on disappearance of rings, at least	4

SATURN'S SATELLITES.
No.	Name.	Sidereal Revolution.				Distance. Saturn's radius = 1.	Discoverer.	Year of Discovery.
		d.	h.	m.	s.
1	Mimas	0	22	36	18	3.1408	Herschel	1789
2	Enceladus	0	8	53	3	4.0319	Herschel	1789
3	Tethys	1	21	18	33	4.9926	Cassini	1684
4	Dione	2	17	44	51	6.3990	Cassini	1684
5	Rhea	4	12	25	11	8.9320	Cassini	1672
6	Titan	15	22	41	25	20.7060	Huyghens	1655
7	Hyperion	21	4	20	0	25.0290	Bond & Lassell	1848
8	Japetus	79	7	54	41	64.3590	Cassini	1671

Hyperion discovered by Bond and Lassell on same night, year	1848
Greatest inclination to the plane of the ring (Japetus),	12° 14′
Apparent diameter of the largest. Titan, (diam. of Saturn = 1),	1-10th
Length of telescope with which Huyghens discovered Titan, in feet,	124
Length of telescope with which Cassini discovered Tethys and Dione, in feet,	145

URANUS.
Volume (Earth's = 1)	86.5
Mass (Earth's = 1),	14.251
Density (Earth's = 1),	.167
Diameter (Earth's = 1),	4.575
Diameter~~— — —~~ in miles .	36,216
Diameter~~— — —~~ apparent, mean,	4″.1
Gravity (Earth's = 1),	0.76
Gravity~~— — —~~ bodies fall in one second of time, in feet,	12.3
Light and heat from Sun, perihelion,	.0027
Light and heat from Sun,~~— — —~~ aphelion.	.0025
Polar less than equatorial diameter,	1-9th
Observed by Flamstead in	1690
Discovered by Herschel in	1781
Magnitude of Uranus as a star (occasionally seen with naked eye),	6th
Distance from the Sun, mean, in miles,	1,822,328,000
Distance from the Sun, mean,~~— — —~~ (Earth's = 1),	19.18239
Distance from the Sun, mean, in miles,~~— — —~~ maximum	20.07630
Distance from the Sun, mean, in miles,~~— — —~~ minimum,	18.28848
Eccentricity of orbit (semi-axis major =1),	0.04667938
Longitude of perihelion,	167° 31′ 16″.1
Longitude of perhilion,~~— — —~~ annual increase	2″.28
Longitude of ascending node,~~— — —~~	72° 59′ 35″
Longitude of ascending node,~~— — —~~ annual decrease,	36″.05
Inclination of orbit to ecliptic.	46′ 28″.44
Incilination of orbit to ecliptic,~~— — —~~ annual increase,	0.03
Motion, mean daily,	42″.35
Motion,~~— — —~~ in 365 days.	4° 17′ 45″
Inclination of axis to ecliptic,	unknown
Rotation on axis,	unknown
Revolution, sidereal, in days,	30686.820829
Revolution.~~— — —~~ synodical,	369.656
Mean arc of retrogradation,	3°.36

URANUS SATELLITES.
No.	Name.	Sidereal Revolution.				Mean Apparent Distance.	Discoverer,	Year of Discovery.
		d.	h.	m.	s.	″
1	Ariel	2	12	29	21	13.54	Lassell	1851
2	Umbriel	4	3	28	8	19.28	Lassell	1851
3	Titania	8	16	56	31	31.44	Herschel	1787
4	Oberon	13	11	7	13	42.87	Herschel	1787

Additional satellites seen by Herschel, but not re-observed,	4
Direction of movement of satellites	retrograde
Inclination of the orbits of Titania and Oberon to ecliptic,	78° 58′
Distance from the planet -when satellites become invisible (Herschel),	14″
IMagnifying power required for sustained view,	300

NEPTUNE.
Volume (Earth's = 1),	76.6
Mass (Earth's = 1), .	18.900
Density (Earth's = 1),	.321
Diameter (Earth's = 1),	4.246
Diameter~~— — —~~ in miles,	33,610
Diameter~~— — —~~apparent, mean,	2.″4
Gravity (Earth = 1),	1.36
Gravity~~— — —~~ bodies fall in one second, in feet,	21.8
Light and heat from Sun, perihelion,	.0011
Light and heat from Sun~~— — —~~, aphelion,	.0011
Year in which Adams computed its place within 2 degrees,	1845
Year in which Leverrier computed its place,	1846
First observed by M. Galle, from Leverrier's indications, 23d Sept.,	1846
Observed by M. Challis, but not recognised, from Adams' indications, 4th Aug.,	1846
Observed as a fixed star by Lalande in	1795
Magnitude as a star,	7-8th
Disc seen with a magnifying power of	150
Distance from the Sun, mean in miles,	2,853,420,000
Distance from the Sun,~~— — —~~ mean (Earth's = 1),	30.03627
Distance from the Sun, mean in miles,~~— — —~~ maximum,	30.29816
Distance from the Sun, mean in miles,~~— — —~~ minimum,	29.77438
Eccentricity of orbit (semi-axis major = 1),	.0087193
Longitude of perihehon, epoch 1854,	47° 17′ 58″
Longitude of ascending node.	130° 10′ 12″
Inclination of orbit.	1° 46′ 59″
Motion, mean daily,	21″.6
Motion~~— — —~~ in 365 days,	2° 11′ 24″
Inclination of axis to ecliptic,	unknown
Rotation on axis.	unknown
Revolution, sidereal, in days,	60126.722
Revoulution„ synodical,	367.488

NEPTUNE'S SATELLITE.
Sidereal revolution,	5^d. 24^h. 0^m. 17^s.
Sidereal~~— — —~~ mean distance, apparent,	16″.75
Sidereal~~— — —~~ mean distance, in miles,	232,000
Orbit inclined to plane of ecliptic.	29°
Longitude of the ascending node.	175° 40′

COMETS.
Halley's—Time of perihelion passage, 15th Nov. 1835,	22^h. 41^m. 22^s.
Halley's~~— — —~~ longitude of perihelion,	304° 31′ 32″
Halley's longitude of~~— — —~~ ascending node,	55° 9′ 59″
Halley's~~— — —~~ inclination of orbit to ecliptic,	17° 45′ 5″
Halley's—Eccentricity,	0.967391
Halley's~~— — —~~ semi-axis,	17.98796
Halley's~~— — —~~ period in days, motion retrograde,	27865.74
Encke's—Time of perihelion passage, 9th Aug. 1845,	15^h. 11^m. 11^s.
Encke's~~— — —~~ longitude of perihelion,	157° 44′ 21″
Encke's longtitude~~— — —~~ ascending node,	334° 10′ 33″
Encke's~~— — —~~ inclination to the ecliptic,	13° 7′ 34″
Encke's~~— — —~~ semi-axis,	2.21640
Encke's~~— — —~~ eccentricity,	0.847436
Encke's~~— — —~~ period, motion direct,	1203^d.23
Biela's — Time of perihelion passage, 11th Feb. 1846,	0^h. 2^m. 50^s.
Biela's~~— — —~~ longitude of perihelion,	109° 5′ 47″
Biela's longitude of~~— — —~~ ascending node,	245° 56′ 58″
Biela's~~— — —~~inclination to the ecliptic,	12° 34′ 14″
Biela's~~— — —~~ semi-axis,	3.50182
Biela's~~— — —~~ eccentricity,	0.755471
Biela's~~— — —~~ period, motion direct,	2393^d..52
Faye's—Time of perihelion passage, 17th Oct. 1843,	3^h. 42^m. 16^s.
Faye's~~— — —~~ longitude of perihelion,	49° 34′ 19″
Faye's longitude~~— — —~~ ascending node,	209° 29′ 19″
Faye's~~— — —~~ inclination to ecliptic,	11° 22′ 31″
Faye's~~— — —~~ semi-axis,	3.81179
Faye's~~— — —~~ eccentricity,	0.555962
Faye's~~— — —~~ period, motion direct,	2718″ 26
DeVico's—Time of passing perihelion, 2d Sept. 1844,	11^h. 36^m. 53^s.
DeVico's~~— — —~~ longitude of perihelion,	342° 31' 15"
DeVico's longitude~~— — —~~ ascending node,	63° 49' 31"
DeVico's~~— — —~~ inclination to ecliptic,	2° 54' 45"
DeVico's~~— — —~~ semi-axis,	3.09946
DeVico's~~— — —~~ eccentricity,	0.617256
DeVico's~~— — —~~ Period, motion direct,	1993^d.09
Brorsen's—Time of passing perihelion, 25th Feb. 1846,	9^h. 13^m. 35^s.
Brorsen's~~— — —~~ longitude of perihelion,	116° 28′ 34″
Brorsen's longitude of~~— — —~~ ascending node,	102° 39‘ 36″
Brorsen's~~— — —~~ inclination to ecliptic,	30° 55′ 7″
Brorsen's~~— — —~~ semi-axis,	3.15021
Brorsen's—Eccentricity,	0.793629
Brorsen's~~— — —~~ period, motion direct,	2042 ^d.24
Number of calculated non-periodic comets up to end of 1855,	206
Number~~— — —~~ with short periods,	12
Number~~— — —~~ with medium periods (Halley's included),	5
Number~~— — —~~ with long periods, probably	10
Number~~— — —~~ moving in hyperbolas,	3
Number~~— — —~~ of comets observed down to 1850,	607
Number~~— — —~~ to which periods have, with probability, been assigned, about	30
Probable number of comets, supposing perihelia equally distributed within the sphere of the orbit of Neptune,	17,558,424
Biela's comet separated into two on 13th January	1846
Biela's comet~~— — —~~ interval between the two parts on 5th March,	9′ 19″
Biela's comet~~— — —~~ earth escaped collision in 1832 by	30^d.
Biela's comet~~— — —~~ on return in 1852, the two parts were separated, in miles	1,250,000
Length of tail of great comet of 1680 in miles,	140,000,000
Length of tail of great comet of 1680~~— — —~~ in arc,	90°
Time in which tail was developed, in days,	2
Number of tails of comet of 1744,	6
Maximum limit of density of Donati's comet,	0.00000017
Arc described by comet of 1472 in a day,	40°
Comet of 1680, distance from Sun at perihelion (Sun's diameter = 1),	1-6th
Comet of 1680,~~— — —~~ heat, according to Newton (red hot iron = 1),	2000
Comet of 1680,~~— — —~~ heat, according to Newton, time required to lose it, in years,	50,000
Halley predicted the return of the comet of 1531 and 1607 in	1759
Halley's comet, maximum length of tail, 15th Oct., 1835,	20°
Halley's comet, length on 5th Nov. 1835 (perihelion 15th Nov.),	2° 30′
Halley's comet,~~— — —~~ jet and tail commenced	Oct. 2
Halley's comet,~~— — —~~ oscillation of jet obvious in the course of	1^h.
Halley's comet,~~— — —~~ invisible after the perihelion, in months,	2
Halley's comet,~~— — —~~ diameter of disc when seen, not including coma,	2′
Halley's comet,~~— — —~~ increase of volume of illuminated space during six days, from Jan. 25,	40 times
Return of Charles V. comet of 1556, predicted by Hind in period	1856-61
Period of Encke's comet, shortening at the rate, per revolution, of	O^d..11
Lexell's comet of 1770, period in years,	5.5
Lexell's comet of 1770,~~— — —~~ thrown out of the system by attraction of Jupiter in	1779
Lexell's comet of 1770,~~— — —~~ distance from Sun at perihelion (Sun's radius = 1),	1-7th
Lexell's comet of 1770,~~— — —~~ angular diameter of Sun at perihelion,	121° 32"
Lexell's comet of 1770,~~— — —~~ disc of Sun at perihelion (disc from Earth = 1),	47,000
Lexell's comet of 1770,~~— — —~~ heat at perihelion (heat of 32 inch burning lens = 1),	25
Lexell's comet of 1770,~~— — —~~ velocity at perihelion, miles, in one second,	366
Lexell's comet of 1770,~~— — —~~ tail stretching to the Earth's orbit, whirled round in two hours,	180°
Lexell's comet of 1770,~~— — —~~ radius of head on 29th March, in miles,	47,000
Lexell's comet of 1770,~~— — —~~ length of tail,	150,000,000
Lexell's comet of 1770,~~— — —~~ breadth of tail,	3,000,000
Periodic comets, all direct when inclination under	17°
Comets calculated before 1849, direct,	94
Comets calculated before 1849, retrograde,	100
Great comet of 1861, distance from the Earth on June 30, .	17,000,000
Great comet of 1861,~~— — —~~ surmised by Hind that the Earth passed through its tail,	30th June
Great comet of 1861,~~— — —~~ length of tail as seen at Rome	118°
Great comet of 1861, length of tail~~— — —~~ as seen at Paris	45°
Great comet of 1861,~~— — —~~ polarisation of tail strong, but no trace in nucleus till	3d July
Great comet of 1861,~~— — —~~ tail seen to flicker and disappear for an instant.	4th July
Encke's comet, before perihelion, diameter diminished in two months to	1-90th
Encke's comet~~— — —~~ after perihelion, diameter increased in six days from 1 to .	40
Rotation of comet of 1825 (doubtful),	19^h. 37^m.
Mass of Lexell's comet less than (Earth's = 1)	1-5000th
Chances unfavourable to collision between earth and a comet (comet's diam. = l-4th of earth's),	281,000,000

DOUBLE STARS.
Number of binary systems with assigned periods, about	15
Period of Castor, with semi-axis of 8", in years,	252
Period of~~— — —~~ χ Ursro Majoris, with semi-axis of 3″.8	59
Period of~~— — —~~ γ Virginis, with semi-axis of 3″.6,	182
Causes of colour in stars, intrinsic and complementary,	2

NEBULÆ.
Number of stars covered by the Moon in parts of the Milky Way,	2000
Number of stars~~— — —~~ in some clusters,	50,
Number of typical forms of nebulæ (globular and spiral),	2
Hour of ascension richest in nebulæ,	12
Nebula in Andromeda, largest elliptical nebula visible to naked eye.
Nebula in Andromeda,„ dark streaks running parallel to longer axis,	2
Largest annular nebula in Lyra.
Planetary nebulæ, number of, about	25
Planetary nebulæ,~~— — —~~ largest, distance from β Ursæ Majoris,	12′
Planetary nebulæ,~~— — —~~ largest, apparent diameter,	2′ 40″
Light of nebula of 1' diameter if as bright as the Sun, in full Moons,	780
Double nebulæ, probable physical connexion as in double stars.
Most brilliant nebulous star in Andromeda, No.	65
Regions of amorphous nebulse — Orion, Argo, Saggitarius, Cygnus,	4
Nebula in sword-handle of Orion, discovered by Huyghens in	1656
Nebula in sword-handle of Orion,~~— — —~~ diameter, horizontal,	30′
Nebula in sword-handle of Orion,~~— — —~~ diameter,vertical,	24′
Variable nebula,	1

METEORIC ZONES.
Zodiacal light, maximum distance of vertex from Sun,	90°
Zodiacal light,~~— — —~~ maximum breadth at base,	30°
November meteors, passing through γ Leonis, period,	12th-14th
Number of zones of asteroids,	3

FIXED STARS.
Magnitude of the smallest stars visible,	7th
Magnitude of the~~— — —~~ stars visible by the most powerful telescopes,	16th
Light of a star of the 6th magnitude (1st magnitude = 1),	1-1OOth
Number of stars of 1st magnitude,	24
Number of stars of 1st magnitude,~~— — —~~ 2d magnitude,	50-60
Number of stars of 1st magnitude,~~— — —~~ 3d magnitude,	200
Number of stars~~— — —~~ total registered to 7th magnitude, about	15,000
Number of stars~~— — —~~ total visible in Herschel's 20-feet telescope,	5,500,000
Rate at which light travels per second, in miles,	200,000
Time required by light to traverse the distance of a star with one second of parallax, in years,	3^y. 83^d.
Corresponding distance in billions of miles,	20
Distance of smallest stars seen in telescopes of 75 space penetrating power, measured by light in years,	2,000
Star 61 Cygni, parallax first detected in it, by Bessel,	0″.349
Star 61 Cygni,~~— — —~~ proper motion annually,	5″
Star 61 Cygni,~~— — —~~ distance of component stars,	15″
Star 61 Cygni,~~— — —~~ sum of masses of the component stars (Sun = 1),	0.353
α Centauri, parallax,	0″.9128
α Centauri,~~— — —~~ nearest star, distance measured by light, in years, about	3.5
α Centauri,~~— — —~~ proper motion,	4″
Number of stars to which parallax has been assigned,	9
Probable average distance of stars of 1st magnitude, measured by light, in years,	15.5
Probable average distance of stars of~~— — —~~ 2d magnitude,	28
Probable average distance of stars of~~— — —~~ 3d magnitude,	43
Probable average distance of stars of~~— — —~~ 4th magnitude,	60
Probable average distance of stars of~~— — —~~ 5th magnitude,	84
Probable average distance of stars of 6th magnitude,	120
Nebulæ, proportion of sphere containing one-third of whole mass, near north pole of the galaxy,	1-8th
Largest proper motion, 1830, Groombridge,	7″
Diameter of the Sun removed to a distance corresponding to one-second parallax,	0″.0093
Light of Sirius (Sun's = 1 at the same distance),	63
Light of the Sun (Sirius = 1) at the Earth,	20,000,000,000
Variable star Algole, period,	2^d 20^h 48^m
Variable star Algole,~~— — —~~ variation in magnitude,	2.4
Variable star~~— — —~~ δ Cephei, period,	5^d 8^h 47^m
Variable star δ Cephei,~~— — —~~ variation in magnitude,	3.5
Variable star~~— — —~~ β Lyræ., period,	12^d 23^h 53^m
Variable star, β Lyræ.~~— — —~~ variation in magnitude,	3.4
Number of variable stars, with assigned periods, about	6O
Double stars, odds against one chance combination of 4″ closeness,	9570 to 1
Double stars,~~— — —~~ number of such combinations, upwards of	100
Sun's distance from Alcyone, the centre of the stellar system (Mædlar), (radius of Earth's orbit = 1),	34,000,000
Sun's~~— — —~~ time of revolution round Alcyone, in years,	19,256,000
Sun's~~— — —~~ velocity in space (Earth's annual motion = 1),	1.4
Sun, point in Hercules, to which it is moving,
Sun, point in Hercules, north declination,~~— — —~~	34° 37′
Sun, point in Hercules, right ascension,~~— — —~~	259°'90

TELESCOPE.
Lord Rosse's Great Reflector, diameter of mirror, in feet,	6
Lord Rosse's Great Reflector,~~— — —~~ thickness of mirror, in inches,	5
Lord Rosse's Great Reflector, focal length, in feet,	54
Lord Rosse's Great Reflector~~— — —~~ length of tube, in feet,	56
Lord Rosse's Great Reflector~~— — —~~ diameter of tube, in feet,	7
Lord Rosse's Great Reflector.~~— — —~~ weight of speculum, in tons,	3
Lord Rosse's Great Reflector.~~— — —~~ expense,	£12,000
Cambridge, U.S., refractor, diameter of object glass, in inches,	15.125
Cambridge, U.S., refractor,~~— — —~~ length of tube, in feet,	23
Cambridge, U.S., refractor,~~— — —~~ magnifying powers,	180-2000
Cambridge, U.S., refractor,~~— — —~~ weight in tons,	3
Cambridge, U.S., refractor,~~— — —~~ diameter of declination-circle, in inches,	26
Cambridge, U.S., refractor, diameter of~~— — —~~ hour circle,	18
Cambridge, U.S., refractor,~~— — —~~ cost,	£4,000
Object-glass by Clarke, diameter, in inches,	18.5
Object-glass by Clarke, diameter,~~— — —~~ contract price,	£2237
Diameter of object-glass in process of execution by Cooke, in inches,	24

THE END

[1] In consequence of this remarkable relation, the 1st, 2d, and 3d satellites can never be eclipsed all at once.

[1]