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upon our army near Alexandria, the French again, on the 21st of March, made a second advance, which was contested with unusual obstinacy, and they were again forced to retreat. On this memorable occasion, he received a mortal wound in the thigh, which he concealed until the enemy were totally routed, when he fell from his horse, through loss of blood. He was conveyed from the field of battle on board the admiral's ship, where he died on the 28th, and was interred under the Castle of St. Elmo, in La Valetta, in the island of Malta.

The following just and admired tribute to his memory was contained in the despatch from Lord Hutchinson, who succeeded him in the chief command: We have sustained an irreparable loss in the person of our never to be sufficiently lamented commander in chief, Sir Ralph Abercrombie; who was mortally wounded in the action, and died on the 28th of March. I believe he was wounded early; but he concealed his situation from those about him, and continued in the field giving his orders with that coolness and perspicuity which had ever marked his character, till long after the action was over, when he fainted through weakness and loss of blood. Were it permitted for a soldier to regret any one who has fallen in the service of his country, I might be excused for lamenting him more than any. other person; but it is some consolation to those who tenderly loved him, that, as his life was honourable, so his death was glorious. His memory will be recorded in the annals of his country; will be sacred to every British soldier, and embalmed in the recollection of a grateful posterity.'

There is a handsome monument to his memory in St. Paul's Cathedral, unanimously voted by the House of Commons; and a pension of £2000 was settled on his family.

29.-LOW SUNDAY.

It was a custom among the primitive Christians,

on the first Sunday after Easter-Day, to repeat some part of the solemnity of that grand festival; whence this Sunday took the name of Low Sunday, being celebrated as a feast, though in a lower degree.

Astronomical Occurrences

In MARCH 1818.

THE Sun enters Aries at 44 m. after 4 in the morning of the 21st of this month; and his rising and setting will take place as specified in the following

TABLE

Of the En's Rising and Setting for every Fifth Day.

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When the mean time is to be found from that marked by a good sun-dial, the quantities in the following table must be used for the times specified, and those for intermediate periods found by proportion.

TABLE.

Sunday, March 1st, to the time by the dial add

Friday,

6th,

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1 m. before 1 morning.

8 m, after 1 afternoon.

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Moon's Passage over the Meridian.

If the weather permit, the Moon may be seen on the first meridian at the following convenient times for observation during the present month.

March 14th, at 40 m. past 5 evening.

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15th, - 31
16th, - 24
17th, 17
18th,
19th, - 59
20th, - 49
28th,

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Eclipses of Jupiter's Satellites.

There will only be one eclipse of the first and one of the second satellite visible at Greenwich this month, and these will happen as follows:

IMMERSIONS.

1st Satellite, March 29th, at 19 m. after 5 morning.

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On the 2d of this month Venus and Saturn will be in conjunction, the former planet being 13' north of the latter. Venus will also be in her superior conjunction at half past 11 on the night of the 12th. The Moon and Mars will also be in conjunction at 10 m. past 3 in the morning of the 15th. On the 16th, Mercury and Saturn will likewise be in conjunction, the former being 34' north of the latter. Mars will be in quadrature at half past 8 in the evening of the 16th. The Georgium Sidus will also be in quadrature at 45 m. after 4 on the morning of the 11th, and stationary on the 25th.

On the DISTANCES, MAGNITUDES, MOTIONS, &c., of the HEAVENly Bodies.

The principal use to which astronomers apply the transits of Venus, of which we have treated in the

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two preceding months, is in determining the distance of the Sun from the earth by means of his parallax, which, on account of its smallness, they have in vain attempted to ascertain by various other methods. The principal obstacles arose from the minuteness of the angles, and which could not be determined with sufficient accuracy by the nicest instruments. To ascertain the real distance of the Sun is undoubtedly one of the most important problems in astronomy, and one of the most incomprehensible to those who are unacquainted with the subject. The difficulty, however, entirely vanishes when the Sun's horizontal parallax is accurately determined; for this is the angle at the centre of the Sun which is subtended by a radius of the earth, forming a right angle with the line supposed to join the centres of these two bodies, and, this radius being known, all the angles and one side of that triangle are given; and consequently the whole problem resolves itself into a simple proportion in plane trigonometry. Hence if the radius of the earth be taken for unity, we shall have the distance of the Sun in the same terms, by saying,

as tan. 8"-7: rad. :: 1 : 23742.605,

the number of terrestrial radii in the distance between the centres of the earth and Sun: this is what is usually called its comparative or relative distance, on account of the assumed unit; but if this number be multiplied by 3979, the English miles in the earth's semidiameter, we shall have the absolute distance in English miles equal to 94471825, or near 94 millions.

Having thus determined the distance of one of the heavenly bodies, considering the earth as a planet, those of the others are easily found from the duration of their sidereal revolutions, by means of one of those celebrated laws which were discovered by Kepler and demonstrated by Newton; viz. that the squares of the times of their revolutions are proportional to the cubes of their mean distances. Hence the time which each of the planetary bodies occupies in mak

ing one complete revolution in its orbit being found by observation, and the distance of any one of them ascertained, the proportion affords a ready means of finding all the others.

The first object is, therefore, to determine the duration of each of these revolutions; and the most simple and direct means of accomplishing this is to observe the interval of time which elapses between two consecutive passages of the planet through the. same node. As the nodes are subject to variation, it is necessary to take this into the account for the interval between the observations. As the planetary motions are also liable to other perturbations, their mean movements should be concluded from a series of observations comprehending a great number of revolutions; so that the periodic inequalities being several times compensated during the interval, what error still remains in the definitive result may be rendered insensible by being divided among those revolutions. The following are the periodic times of the planetary revolutions, thus determined according to the most eminent astronomers :

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The times of revolution and the distance of the earth from the Sun being thus known, the distances of all the others are found by the proportion above stated. Thus, if the respective distances of any two

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