It then decreases to the 26th, being, on that and the preceding day, about twenty-nine minutes and a half; and it afterwards increases, being, on the last midnight, half a degree and twentytwo minutes. The Sun is at the equinoctial point of (r), at eighteen minutes past four after noon of the 20th.

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

APRIL, 1820.

THE mode of correction, which I have recommended for the errours, that have appeared already or may appear hereafter in the publications from the two most celebrated observatories in the world, has, from the instance produced, decidedly proved, that it may be depended upon. But still it may strike the reader, that he is not to be determined by a single instance, though that instance is confirmed by the correction made by the editers themselves of the Nautical Almanack. The importance of the subject will therefore justify us in trying another instance; and the Nautical Almanack for this year affords us such a quantity, that there will be no difficulty in finding one. One occurs in the distance of the Moon on the 1st of July, where the errour is so palpable, that it must strike the most superficial observer. For the distance of the Moon from a star is made to

be the same in degrees both at nine o'clock at night, and at midnight. According to the plan I have proposed, the superior officer of a vessel at sea, having determined to take an observation at night of this day, of the distance of the Moon from Aldebaran, will previously have required from the inferior officers to inform him, whether the distances in the tables of the Nautical Almanack are correct or not; and they would naturally employ themselves in the investigation in the following manner :

The inspection of the column of differences shows at once a palpable errour in the degrees, for it is evident, that no one difference can exceed two degrees, and in the third line it is upwards of three degrees. On noticing that the

three last differences agree so far, in being nearly one degree and three quarters, he will naturally assume that quantity as his correction for the errour in the place above mentioned. By taking this quantity from the distance at six in the morning, it leaves him 72° 6′ 15′′ for his first corrected distance at nine. He subtracts the same quantity from the distance at nine, 72° 6' 15", and it leaves him 70° 21′ 15′′ for his first corrected distance at midnight. He disregards at present the difference in seconds between his corrected distances, and those in the Nautical Almanack, and writes down 72° in the place of 70° in his first column, and makes no farther correction as yet in that column, and corrects his column of differences accordingly thus:

On observing now his columns of differences he perceives, that in the six last lines, there is a gradual diminution of the preceding number by a small quantity between ten and twenty seconds only, but the difference between the two first numbers of his second column is nearly twenty minutes. This satisfies him, that there must be an errour in the distance stated in the Nautical Almanack at noon to be 77° 2' 11". For the first mode of correcting this errour he considers, what ought to have been the number in his column of differences instead of 1° 25' 34", which is evidently erroneous, and perceiving that the difference between the adjoining last numbers of this column does not exceed, in one instance only, fifteen seconds, and that it apparently is increasing, he assumes fourteen se conds as the difference between his two first numbers in the column of differences. By adding therefore fourteen seconds to his second number in this column, namely, 1° 45′ 22′′, he obtains the number 1° 45′ 36", for the first number in this column. Consequently, he correots the distance at noon, by adding this number to the distance at three in the afternoon, namely, 75° 36′ 37′′, and it gives him 77° 22′ 13′′,