Two heavenly bodies are in conjunction' (6) when they have the same Right Ascension, or are on the same meridian, i. e., when one is due north or south of the other; if the bodies are near each other as seen from the earth, they will rise and set at the same time; they are in "'opposition" (8) when in opposite quarters of the heavens, or when one rises just as the other is setting. "Quadrature" is half way between conjunction and opposition. By greatest elongation' is meant the greatest apparent angular distance from the sun; the planet is then generally most favorably situated for observation. Mercury can only be seen with the naked eye at this time. When a planet is in its "ascending" (Q) or 'descending" (8) node it is crossing the plane of the earth's orbit. The term "Perihelion means nearest, and "Aphelion" farthest, from the sun. An occultation" of a planet or star is an eclipse of it by some other body, usually the moon.

1.-ECLIPSES.

There will be six Eclipses in the year 1898; three of the sun and three of the moon, as follows: 1. A partial Eclipse of the Moon January 7, visible in the eastern portions of North and South America, and in Europe, Asia, and Africa.

The point of first

Magnitude of the Eclipse 0. 157 of the Moon's diameter, on the southern limb. contact with the shadow is 1690 from the northern point of the Moon's limb toward the east, and the last contact 1420 toward the west.

2. A total Eclipse of the Sun January 21, invisible in America. The path of the central Eclipse begins near a point in Lat. 110. 2 N. and Long, 90, 8 E., which is in Western Africa; it then moves eastward, bearing a little to the south through the centre of that continent unti. it enters the Arabian Gulf, where its course changes to northeast, crossing India, directly ve. the city of Allahabad, Western China, and terminates in Easteri Siberia. It will be visible as a partial Eclipse over nearly the whole of Asia and Africa and the eastern part of Europe, including Italy, Greece, Turkey, Austria, Russia, and portions of France, Germany, and Sweden.

3. A partial Eclipse of the Moon July 3, invisible in America, visible in Europe, Asia, and Africa.

4. An Annular Eclipse of the Sun July 18, visible in the South Pacific Ocean, the northern part of New Zealand, Patagonia, and the southern portions of Chile and the Argentine Republic. 5. A partial Eclipse of the Sun December 12-13, visible only in the Antarctic Ocean. Magnitude of the Eclipse 0. 023 of the Sun's diameter.

This Eclipse is remarkable as the last of a cycle of Eclipses which began near the North Pole about 1260 years ago. At its last return, December 1, 1880, its magnitude was 0. 042 of the Sun's diameter.

6. A total Eclipse of the Moon December 27, visible generally throughout North and South America, Europe, Asia, and Africa.

Magnitude of Eclipse 1. 384 of the Moon's diameter. The point of first contact with the shadow is 1120 from the northern point of Moon's limb toward the east, and the point of last contact is 950 toward the west.

The Ancient and Modern Year.

THE Athenians began the year in June, the Macedonians in September, the Romans first in March and afterward in January, the Persians on August 11, the ancient Mexicans on February 23, the Mohammedans in July. The Chinese year, which begins early in February, is similar to the Mohammedan in having 12 months of 29 and 30 days alternately; but in every nineteen years there are seven years which have 13 months. This is not quite correct, and the Chinese have therefore formed a cycle of 60 years, in which period 22 intercalary months occur.

THE mean obliquity of the ecliptic for the year 1898 is 23° 27′ 8ꞌꞌ, 96. Mean annual diminution, O. 46.

The present accepted value of the solar parallax is 8". 81 at the earth's mean distance, which is 92, 790,000 miles, with a probable error of about 75,000 miles more or less.

The eccentricity of the earth's orbit is 0. 016771; we are therefore 3, 112, 560 miles nearer to the sun at perihelion (January 1) than at aphelion (about July 1).

Length of the sidereal year, 365 days, 6 hours, 9 minutes, 9.6 seconds of mean time.

Length of the tropical year (from equinox to equinox), 365 days, 5 hours, 48 minutes, 46.07 seconds of mean time.

Mean distance from earth to moon, 238, 850 miles.

The length of a second's pendulum, that is, one which vibrates once in a second, in vacuo,

ASTRONOMICAL CONSTANTS-Continued.

at any place whose latitude is 1, is 39.01254+0.20827 sinal inches. At New York it is 39. 1013 inches. The acceleration of gravity in one second of mean solar time is 32.086528 +0.171293 sin?? feet. The half of this is the distance through which a body falls (in a vacuum) in one second. The velocity of light is 186, 330 miles per second.

Light requires 8 minutes and 18 seconds to pass from the sun to the earth when at its mean distance, as given above; therefore, when we look at the sun we see him not where he actually is, but where he was about 8 minutes and 18 seconds ago; his true place is then always in advance of his apparent place.

Pole Star.

MEAN TIME OF TRANSIT (AT NEW YORK) AND POLAR DISTANCE OF POLE STAR.

From June 16 to August 1 both the upper and lower transits take place during daylight. The azimuth at the time of greatest eastern or western elongation can be easily computed from the formula:

sin A =

sin p
COS I

where A denotes the azimuth, p the polar distance, and the latitude of the place.

DATE OF GREATEST ELONGATION.

To find the time of greatest eastern or western elongation, let H denote the hour angle, and / and p as before, then we shall have

And the hour angle in mean time is

cos H= tan p tan l.

Hm HX 0·0664846.

This quantity, Hm, added to or subtracted from the time of transit given above, according to the elongation required, will give the mean time of the greatest elongation at any place whose north latitude is 1.

Star Table.

FOR IDENTIFYING THE PRINCIPAL FIXED STARS

NAME OF STAR.

Upper. Lower.

H. M.

N 28 31

H. M.

NAME OF STAR.

-1 18.0 +10 40.0 a Leonis (Regulus).
N 14 37 1 13.2 +10 44.8 a Virginis (Spica).
N 55 58 0 42.2 +11 15. 8 aBootis (Arcturus)
N 22 59+0 40.0 +12 38, 08Ursa Minoris.
N 40 341 39.9 +13 37.9 aCorona Borealis..
N 16 18 3 8.2 +15 6.2 aScorpii (Antares).
N 45 54 3 47.115 45.1 aLyra (Vega),
S8 198 47.6 +18 45.6 a Aquile (Altair).
N 7 23+ 4 27.6 +16 25. 6 aCygni (Deneb).
S 16 35+ 5 18.4 +17 16.4 aCephei
N 7 6 5.7 +18 3.7 a Aquarii
N 28 16+6 16.6 +18 14.6 a Piscis Aus.
N 5296 11.6 +18 9.6 a Pegasi (Markab).

Upper. Lower.
H. M.
N 12 28+ 8 40.1 +20 38.1
S 10 3711 56.5 +23 54,5
N 19 43 +12 47.5 +0 45.5
N 74 35+13 27.5+1 25, 5
N 27 4 +13 49.71 47.7
S 26 12 14 59. 32 57.3
N 38 4117 9.3 5 7.3
N 8 36 +18 21.46 19.4
N 44 55 +19 13.57 11.5
N 62 9+19 51.57 49.5
S 0 49 +20 35,8 +8 33,8
S 30 10 +21 27.1 +9 25.1
N 14 39 21 34.79 32.7

the numbers

To find the time of the star's transit add or substract, according to the sign, In the second column of figures to the date of the transit of the pole star given above. Thus, for a Andromeda February 1st. Lower Transit of Polar Star is 4 h. 34.9 m. A. M., to which add 10 h. 40 m. and we have 3 h. 14.9 m. P. M.; for December 1st, we find 7 h. 21. 1 m. P, M., etc.