23.

C.R.

represented. About the middle of February, Orion will be on the meridian about eight in the evening; and in the month of March, at the same hour, considerably to the west of it; but all the adjacent stars and constellations may be traced at this time in the manner already described. The stars and constellations delineated on this map comprehend a space in the heavens extending in breadth, from north to south, about fifty degrees; namely, from thirty-three degrees of north declination to seventeen degrees south; and in length, from west to east, about sixty degrees. The equator runs through this portion of the heavens in the direction a b, or nearly corresponding to the line L M, so that it passes very near to the upper star in the belt of Orion. The degrees of north and south declination* from the equator are marked on the margin.

Plate II. represents another portion of the heavens as it appears about the beginning of September. It includes some of the larger stars belonging to the constellations Cygnus, Lyra, Cerberus, Serpentarius, Aquila, Hercules, and Corona Borealis. At ten o'clock in the evening of the 1st of September, the star Altair, in the constellation of Aquila, or the Eagle, will be nearly on the meridian, at an elevation above the horizon of about forty-six degrees. This star, which is between the first and second magnitude, is situated near the east or left-hand side of the map, near the bottom, and has a small star to the south, and another to the northwest of it. A line drawn from T to U passes through the star Altair, and a line from V to W passes through the meridian, at the hour supposed.

The seven stars which are nearest Altair, towards the south, and west, and northwest, belong to the constellation of Aquila. All the stars on the map which are to the right hand of Altair are west of the meridian. A line drawn from X to Y, near the top of the map, passes through Denib, a bright star of the second magnitude in the constellation of Cygnus, or the Swan, which is the star next the left-hand

*The declination of a heavenly body is its distance north or south from the equinoctial or equator, and corresponds to latitude on the terraqueous globe, which is the distance of a place from the equator. The latitude of a heavenly body is its distance north or south of the ecliptic, or apparent path of the sun, which forms an angle of 23 1-2 degrees with the equinoctial.

side, nearly due north from Altair, at the distance of thirtysix degrees; the other four stars adjacent to it belong to the same constellation. A line drawn from A to B passes through the star Vega, or a Lyra, a brilliant star of the first magnitude in the constellation of the Harp. The six small stars to the southeast of it likewise belong to this constellation. The stars on the right, or to the westward of Vega, belong chiefly to the constellation of Hercules. A line drawn from C to D passes through the principal star of Corona Borealis, or the Northern Crown, named Alphacca, which is of the third magnitude, and near the right-hand side of the map. The stars north and east from it belong to the same constellation. West from Alphacca is Mirac, at the distance of eleven degrees; and southwest of Mirac, at the distance of ten degrees, is Arcturus, a bright star of the first magnitude, which is then about eighteen degrees above the western horizon. Both these stars are in the constellation Bootes, but they are not within the limits of the map. A line drawn from F to G passes through Ras Algethi, a star of the second magnitude, and the principal star in the constellation of Hercules, which is twenty-five degrees southeast of Corona Borealis. A line from Hto I passes through Ras Alhague, a star of the second magnitude in the head of Serpentarius. This star is five degrees east by south of Ras Algethi. Most of the other stars to the south and east in the map belong to Serpentarius. Various other remarkable stars may be seen at this time besides those noted in the map, particularly the square of Pegasus, or the Flying Horse. About fifty-three degrees nearly east from Altair is Markab, a star of the second magnitude; sixteen and a half degrees east of Markab is Algenib, another star of the second magnitude; fourteen degrees north of Algenib is Alpheratz, and fourteen degrees west of Alpheratz is Scheat, both of them stars of the second magnitude. These four stars, of nearly equal magnitudes, form the Square of Pegasus, and appear nearly half way between the eastern horizon and the meridian.

All the stars alluded to above may likewise be seen during the months of July and August, when they will appear in a more easterly position than at the time stated above; and in the month of October, at eight o'clock, and in November, at six o'clock in the evening, they will be seen nearly in the positions which have been now represented.

from Alphace

and southwes Arcturus, a b about eightee these stars ar Iwithin the lir

passes throug and the princi is twenty-five from H to II ond magnitud degrees east stars to the so Various other sides those no asus, or the F ⚫east from Alta sixteen and a star of the sec

genib is Alph is Scheat, both four stars, of Pegasus, and horizon and th

All the star the months of more easterly the month of six o'clock in sitions which 1