GEOGRAPHY OF THE HEAVENS FOR NOVEMBER.

BY CHANCELLOR M. B. GOFF, Western University of Pennsylvania.

THE SUN

Has again returned to about the same place that it occupied this time last year; and as a result, we find that it rises and sets within a minute or two of the times given on the 1st, 16th, and 30th of last November. For the present month, it rises at 6:31, 6:48, and 7:04 a. m., and sets at 4:57, 4:41, and 4:34 p. m., respectively, on the dates mentioned. We find also that on the 16th day breaks as late as 5:11 a. m. Other phenomena connected with the sun are as follows: On the 4th, at 3:00 p. m., it is in superior conjunction with Mercury, rendering of course by its great brilliancy that little planet invisible. On the 13th it is in opposition to Neptune; that is, 180° distant. So that, on that date, the planet might be said to rise as the sun sets, or set as the sun rises. On the 20th, at 3:00 a. m., it is 90° east of Jupiter, so that if both had the same declination Jupiter must rise about six hours before the sun. But since the declination of Jupiter is north while that of the sun is south, the former actually rises nearly eight hours before the latter.

THE MOON

Exhibits the following phases: Full on the 3d, at 3:28 a. m.; last quarter on the 9th, at 6:04 p. m.; new moon on the 17th, at 1:03 p. m.; and first quarter on the 25th, at 5:08 p. m. On the 16th, it rises at 5:31 a. m.; on the 1st, it sets at 4:18 a. m.; and on the 30th, sets at 4:11 a. m. Is nearest the earth on the 4th, at 10:36 a. m., and farthest away on the 19th, at 9:12 p. m. The sun and moon play an important part, in fact, are the sole cause, as is believed, of a singular phenomenon observable in our largest bodies of water. We refer to the Tides, which are an alternate rising and falling of the waters of the ocean, at regular intervals. These have their greatest and least elevation twice a day, and are called High and Low Tides; twice a month, called Spring and Neap Tides; and also twice a year. The rising of the tide is called the Flood and the falling the Ebb tide. Similar tides, whether high or low, occur on opposite sides of the earth at the same time. Thus, if it is high tide at New York it is high tide 180° from New York. The same is true of low tides. The interval between two successive high tides is about twelve hours and twenty-five minutes; or, if we regard the tidal wave as passing entirely around the earth, it would each day reach the same meridian about fifty minutes later than on the preceding day. So that they occur in the course of time, at all hours of the night and day. Now, it is often very important to know just when they will take place. For example, a vessel wishing to enter a harbor where the water is ordinarily too shallow to let her pass, may propose to take advantage of high tide to make her mooring. It has been found that the connection between the tides and the motions of the sun and moon is so intimate that the one evidently depend upon the others, and so accurately has the relation been established that it is a matter of comparative ease to estimate the height of the tide at any given time on any coast of the world. The cause of the tides is the attracting power of the sun and moon. On the principle of universal gravitation the earth is drawn toward these two bodies, and were it a solid mass, all the body would move equally toward them; but as it is partly liquid, and as the attraction of all its parts is not equal, the liquid parts nearest the bodies move faster than the solid part; while the liquid part furthest away not being attracted so strongly as the solid part is left behind, and thus at the same time two waves are formed on opposite sides of the globe. Such tides as these would be called High Tides. At the moment of high water at any given place, the water is, as it were, piled up. And as the amount of water on the earth’s surface is constant, at 90° from this place the waters must be shallower, and thus low tides are created. The foregoing results would be produced, if the sun and moon had the same longitude or if their longitudes differed by 180°. Since these relative positions each occur once at least every month, there are each month two Spring Tides. But there also occurs twice each month a period when the sun and moon are 90° from each other; then instead of their united influence being exerted, it is divided, and the attractions are at right angles to each other. Thus are produced what are called neap tides. The attraction of the sun upon the earth is vastly greater than that of the moon, but on account of the greater inequality of the moon’s attraction, its influence in producing tides is really three times as great as that of the sun. Nor is the tidal wave always directly under the moon, but follows it at various distances, depending much upon the depth of water, the regularity of the channel, the size of the ocean, and the coast along which it moves.

MERCURY,

On the 4th, in superior conjunction with, and on the 16th, at 5:00 a. m., at its greatest distance from the sun; while on the 18th, at 3:53 a. m., it will be 5° 18′ south of the moon. It will rise on the 1st at 6:29 a. m.; on the 16th, at 7:29 a. m.; and on the 30th, at 8:26 a. m., and set on the corresponding days at 4:47, 4:51, and 5:14 p. m., being a morning star for the first four days and evening star for the remainder of the month, and perhaps visible to the naked eye on the last day. Motion for the month direct, and amounting to 46° 56′ 44″. Diameter increases from 4.6″ to 5″.

VENUS

Continues to reign queen of the morning, rising, however, later each day, and rapidly moving to her superior conjunction, her diameter diminishing 3.2″ in twenty-nine days. Her times for rising are these: On the 1st, 3:02 a. m.; on the 16th, 3:31 a. m.; and on the 30th, 4:00 a. m. On the 4th, at 6:00 a. m., she will be 50′ north of Uranus; on the 13th, at 10:00 p. m., nearest the sun; and on the 14th, at 12:38 a. m., 2° 1′ north of the moon.

MARS

Will be evening star during the entire month, and will afford nothing of especial interest. He rises at 8:46, 8:41 and 8:35 a. m., on the 1st, 16th and 30th, respectively; and sets on the same days at 6:06, 5:47 and 5:33 p. m., respectively. His direct motion amounts to 24° 52′ 6″, and his diameter diminishes two tenths of a second of arc. On the 19th, at 8:48 a. m., is 5° 26′ south of the moon.

JUPITER,

On the other hand, grows in interest each day, his diameter increasing from 33.2″ to 36″, and his countenance shedding its light on an average of half the night during the month. His motion is 2° 52′ 14″ direct. On the 11th, at 12:33 a. m., 4° 26′ north of the moon; and on the 26th, at 3:00 a. m., 90° west of the sun. He rises on the 1st at 12:53 a. m.; on the 16th, at 12:00, midnight; and on the 29th, at 11:11 p. m., and is consequently a morning star.

SATURN

Will be morning star, although visible nearly the entire night, and will increase in diameter from 18.8″ to 19.4″. Will have a retrograde motion of 2° 8′ 38″, and on the 5th, at 10:18 p. m., will be 3° 23′ north of the moon. On the 1st, will rise at 7:25 p. m., and on the next morning set at 10:03 a. m.; on the 16th, will rise at 6:22 p. m., and on the 17th, set at 9:00 a. m.; and on the 30th, rise at 5:23 p. m., and set on December 1st, at 8:01 a. m.

URANUS

Is also morning star, rising on the 1st at 3:20 a. m.; on the 16th, at 2:25 a. m.; and on the 30th, at 1:32 a. m., and setting on the afternoon of the same days at 3:22, 2:25 and 1:30 p. m., in the same order. His motion is direct, and amounts to 1° 26′ 27″ of arc. Diameter increases one tenth of a second of arc. On the 3d, at 6:00 a. m., is 50′ south of Venus; and on the 13th, at 3:45 a. m., is 1° 54′ north of the moon.

NEPTUNE.

This distant neighbor of ours, in his far-away home, seems to have exhausted his resources in his early efforts at disturbing the motion of Uranus, and sinking to the common level, now makes his accustomed rounds without attracting any attention from the great mass of the world’s people, and but little from astronomers themselves. But he is still among his companions, and we find him claiming for himself this month the distinction of both a morning and an evening star—the former for the first half of the month, the latter for the remainder. On the 1st, 16th and 30th, he rises at 5:35, 4:35 and 3:38 p. m., respectively, and sets on the mornings of the 2d, 17th, and December 1st, at 7:33, 6:31, and 5:34. On the 3d, at 8:14 p. m., he is 1° 28′ north of the moon; and on the 13th, at 3:00 p. m., 180° west of the sun; that is, in opposition.