Of course, the observer who really wishes to become an astronomer will not rest satisfied by learning only the principal stars shown in these maps. By means of the regular star-maps, such as those of my School Star Atlas, he will be able to explore the depths of all the constellations, having once learned their position and general appearance from the accompanying maps. It will be well for the student to remember that the planets Venus, Mars, Jupiter, and Saturn will at times appear among the constellations here shown. Venus and Jupiter can always be recognized by their superior light, Mars and Saturn by the steadiness with which they shine. The almanac will always show when these planets and Mercury (often very bright in the clear skies of America) are above the horizon, and where they are situate. They never appear except among the zodiacal constellations. For particulars and pictures of the different constellations, and other details associated with the study of the star-groupings, the reader is referred to my "Easy Star Lessons," published like the present maps by Messrs. PUTNAM'S SONS. I have to thank the proprietors of the _Scientific American_ for permission to publish these maps, which originally appeared (though in a slightly different form) in the pages of that excellent magazine. The Latin names of the constellations included in the maps of this series are as follows: THE LITTLE BEAR, URSA MINOR (a, the _Pole Star_; b, g, _the Guardians_). THE DRAGON, DRACO (a, _Thuban_). KING CEPHEUS, CEPHEUS. THE LADY IN THE CHAIR, CASSIOPEIA. THE CHAMPION, PERSEUS (b, _Algol_, remarkable variable). THE CHARIOTEER, AURIGA (a, _Capella_). THE GREATER BEAR, URSA MAJOR (a, b, the _Pointers_). THE HUNTING DOGS, CANES VENATICI (a, _Cor Caroli_). QUEEN BERENICE'S HAIR, COMA BERENICES. THE HERDSMAN, BOOeTES (a, _Arcturus_). THE NORTHERN CROWN, CORONA BOREALIS. THE SERPENT, SERPENS. THE KNEELER, HERCULES. THE LYRE, LYRA (a, _Vega_). THE SWAN, CYGNUS (a, _Arided_; b, _Albireo_). THE WINGED HORSE, PEGASUS. THE CHAINED LADY, ANDROMEDA. THE TRIANGLES, TRIANGULA. THE RAM, ARIES. THE BULL, TAURUS (a, _Aldebaran_; ae, _Alcyone_, the chief _Pleiad_). THE TWINS, GEMINI (a, _Castor_; b, _Pollux_). THE CRAB, CANCER (the cluster between g and d is the _Beehive_). THE LION, LEO (a, _Regulus_). THE VIRGIN, VIRGO (a, _Spica_). THE SCALES, LIBRA. THE SERPENT-HOLDER, OPHIUCHUS. THE EAGLE, AQUILA (a, _Altair_). THE DOLPHIN, DELPHINUS. THE WATER CARRIER, AQUARIUS. THE FISHES, PISCES. THE SEA MONSTER, CETUS (o, _Mira_, remarkable variable) THE RIVER, ERIDANUS. THE GIANT HUNTER, ORION (a, _Betelgeux_; b, _Rigel_). THE LESSER DOG, CANIS MINOR (a, _Procyon_). THE SEA SERPENT, HYDRA (a, _Alphard_). THE CUP, CRATER (a, _Alkes_). THE CROW, CORVUS. THE SCORPION, SCORPIO (a, _Antares_). THE ARCHER, SAGITTARIUS. THE SEA-GOAT, CAPRICORNUS. THE SOUTHERN FISH, PISCIS AUSTRALIS (a, _Fomalhaut_).