from the zenith towards the east-north-east (_see_ the pointers [gamma] and [delta] Cassiopeiae in Map 4, Frontispiece), the cluster being between [delta] Cassiopeiae and [alpha] Persei.
Not very far off is the wonderful variable Algol, now due east, and about 58 deg.

above the horizon.

The variability of this celebrated object was doubtless discovered in very ancient times, since the name Al-gol, or "the Demon" seems to point to a knowledge of the peculiarity of this "slowly winking eye." To Goodricke, however, is due the rediscovery of Algol's variability.

The period of variation is 2d.20h.

48m.; during 2h.14m.Algol appears of the second magnitude; the remaining 6-3/4 hours are occupied by the gradual decline of the star to the fourth magnitude, and its equally gradual return to the second.