THE

AMERICAN ALMANAC,

FOR THE YEAR

1850,

Being the latter part of the 74th, and the beginning of the 75th year of the Independence of the United States of America;

the 6563d year of the Julian Period ;

the latter part of the 5610th, and the beginning of the 5611th year since the creation of the world, according to the Jews; the 2603d year (according to Varro) since the foundation of Rome;

the 2597th year since the era of Nabonassar, which has been as

signed to Wednesday, the 26th of February, of the 3967th year of the Julian Period, which corresponds, according to the chronologists, to the 747th, and, according to the astronomers, to the 746th year before the birth of Christ ; the 2626th year of the Olympiads, or the second year of the 657th Olympiad, beginning in July, 1849, if we fix the era of the Olympiads at 775 years before Christ, or at or about the beginning of July of the year 3938 of the Julian Period; the latter part of the 1266th, and the beginning of the 1267th year (of twelve lunations) since the Hegira, or flight of Mahomet, which, as is generally supposed, took place on the 16th of July, in the year 622 of the Christian era.

6 Conjunction, or having the same Longitude or Right Ascension.

A Quadrature, or differing 90° in

8 Opposition, or differing 180° in

The ascending, U the descending node.

The sign is prefixed to the latitude, or declination, of the Sun, or other heavenly body, when north, and the sign when south; but the former prefixed to the hourly motion of the Moon in latitude indicates that she is approaching, and the latter that she is receding from, the north pole of the ecliptic.

The letters M. A., m. a., denote Morning and Afternoon.

66 north of Equator, (Spring and Summer,) 186 10 59 45

66 south of

(Winter and Autumn,) 178 18 59 9

Length of the tropical year, commencing at

the winter solstice, 1849, and terminating 365 5 58 54 at the winter solstice, 1850,

Mean, or average length of the tropical year, 365 5 48 48

Mean Time at Washing.

ton Obser. vatory.

[The anniversaries marked with an asterisk (*) are to be strictly observed.]

15th, *Beginning of the Passover,

66

Feb. 25,"

Feb. 26, "

Feb. 27,
Mar. 14, "

Mar. 28, "

66 16th, *Second Feast, or Morrow of the Passover, Mar. 29,

66 22d, *End of the Passover, .

"Ijar begins,

. April 3, April 4, " · April 13, " April 30, "

May 12, "

แ

Thammus begins,

66

66 Ab begins,

May 17, "

May 18, "

June 11, "

17th, Fast for the taking of the Temple,. June 27,

"9th, *Fast for the burning of the Temple,

10th, *Fast of the Reconciliation or Atonement,

"15th, *Feast of the Huts or Tabernacles, .

Sept. 8, "

Sept. 9, "

66

66

66

66

66

Year. Names of the Months.

5611 Tisri 16th, *Second Feast of the Huts,

21st, Feast of Palms or Branches,

22d, *End of the Hut or Congregation Feast,

23d, *Rejoicing for the discovery of the Law, Marchesvan begins,

Chisleu begins,

The Jewish year generally contains 354 days, or 12 lunations of the Moon; but in a cycle of 19 years, an intercalary month (Veader) is 7 times introduced, for the purpose of rendering the average duration of the year nearly or quite correct.

The Mahometan Era dates from the flight of Mahomet to Medina, July 16th, A. D. 622.

The Mahometan year is purely lunar; it consists of 12 synodical periods of the Moon, or of 354 days 19 times in a cycle of 30 years, and of 355 days 11 times. The average length of this year is therefore 354 days, which differs only thirty-three seconds from the truth; a degree of exactness that could only have been attained by a long series of observations. But as no allowance is made for the excess of 11 days in the length of a tropical year over the time of 12 revolutions of the Moon, it is obvious that once in about 33 years the above months will correspond to every season and every part of the Gregorian year.

HEIGHT OF THE GREATEST OR SPRING TIDES IN 1850.

Computed by the Formula of Laplace (Mécanique Céleste, Vol. II. pp. 289, Paris ed., and [2858] Bowd. ed.)

The unit of altitude at any place is the height at that place of that tide which arrives about a day and a half after the time of New or Full Moon, when the Sun and Moon, at the moment of conjunction or opposition, are at their mean distance from the Earth, and in the plane of the celestial equator.

This unit of altitude, which must be derived from observation for each place, multiplied by the quantities in the above table, gives the height of the spring tides at that place during the present year.

By the above table it appears that the highest tides of 1850 will be those of Jan. 29, Feb. 28, March 29, Aug. 9, Sept. 8, and Oct. 7.

The actual rise of the tide, however, depends so much on the strength and direction of the wind, that it not unfrequently happens that a tide, which would, independently of these, have been small, is higher than another, otherwise much greater. But when a tide, which arrives when the Sun and Moon are in a favorable position for producing a great elevation, is still further increased by a very strong wind, the rise of the water will be uncommonly great; sufficient, perhaps, to cause damage.

The formula from which these tides were computed is, however, strictly true only for Brest and its vicinity, and must be regarded as a very uncertain approximation for the coast of the United States.