Herschel is a morning star. His latitude, on the 1st, is nine minutes south, in the twentysixth degree of the ninth sign (); and his motion is direct through about a degree and a half, with nearly the same latitude. His nearness to the Sun and small height above the horizon at Sun-rise will prevent many observations on him in the former part of the month, but towards the middle of it the telescope will be directed to him under and to the west of () the twelfth of the Archer. He enters the western limb of the eastern branch of the Milky-way about the 21st. The Moon passes him on the 13th.

This month is distinguished by five planets being above the horizon at the same time, Venus, Jupiter, Saturn, Mars, and Ceres, in this order, from west to east; and about the 20th, they will be all discernible together soon after Sun-set; the latter planet being however too near the horizon to have many observers.

The Sun's apparent diameter, on the 1st, is thirty-two minutes thirty-five seconds and a half; and on the 19th, thirty-two minutes thirty-four seconds. The Moon's diameter, on the 4th, is

during the whole day about twenty-nine minutes and a half; and it thence increases to the 16th, when it is about thirty-three minutes twenty-two seconds; and it decreases to the last day of the month, when it is twenty-nine minutes twenty-six seconds. The Sun enters the eleventh sign () on the 21st, at twenty-eight minutes past one in the morning.

For the position of the fixed stars at any hour of the night, consult the volume for 1806, aecording to the following Table :

FEBRUARY, 1820.

THE establishment of observatories in different parts of the world, and the communication of their observations and calculations, is a very great advantage to astronomy, and after a course of

years will lead to some important results. In their calculations they go on certain principles, and from the near coincidence of the place of the Sun, Moon, and Planets by actual observation, with that assigned to it by calculation, there cannot be a doubt that the principles on which they go are not far from the truth. I must however be not misunderstood on this head. For these calculations will be the same, provided the relative distances of the Planets from the Sun are preserved; but, whether the absolute distances of these bodies are as they are stated in the books, is a question, that may in a future age be determined very differently from what it

is at present. The variation in these distances, as assigned at different preceding ages, is very great, and there may be something not hitherto discovered, which may have rendered our mode of calculation as fallacious as that, which was employed by our predecessers. Time tries the truth and after a sufficient number of transits of Mercury and Venus over the Sun's disk, which in the revolution of ages will be observed with improved accuracy, the distances of the Planets from the Sun may perhaps be ascertained with such precision as to leave little or no doubt upon the subject.

The two observatories of Greenwich and Paris are so near to each other, that the calculated longitudes of the Sun at noon, and the longitudes and latitudes of the Moon at noon and midnight in each place, must very nearly correspond; and the same may be said, with due allowance, on a more important point to navigation, the distances of the Moon from the Sun and certain fixed stars. Hence a very great degree of security is held out to the mariner; and the expense of providing himself with the two works, the Nautical Almanack and the Connaissance des Tems, is so small, that he should not go to sea

on a long voyage without previously procuring these volumes, and comparing them with each other. The utility of this precaution will be seen by an instance or two.

Let us suppose a person to have these two volumes out at sea with him, and to have made the necessary observations on the Moon's distance from Antares, when it is nine o'clock in the morning on the 7th of January at Greenwich, according to his observed distance of the Moon from the star and the distance given in his book: his observed distance is sixty-five degrees five minutes fifty-nine seconds, the same as is placed for that hour. Let the time with him be six in the morning. Consequently, the difference in the time being three hours, his longitude is fifteen degrees. But on comparing together his two books he finds, that the distance of the Moon from Antares at nine o'clock in the morning of this day at Paris is sixty-five degrees fifty-six minutes thirty-four seconds. They cannot both be right. The question is, which should he depend upon? Shall he calculate his from London by these

longitude from Paris or

tables? and if he takes his longitude from the Parisian tables, and then converts it into longitude from Greenwich, he will necessarily find a

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