CANIS MAJOR ("Great Dog"), in astronomy, a constel lation placed south of the Zodiac, just below and behind the heels of Orion. Canis minor, the "little dog," is another constellation, also following Orion and separated from Canis major by the Milky Way. Both these constellations, or at least their principal stars, Sirius in the Great Dog and Procyon in the Little Dog, were named in very remote times, being referred to as the "dogs of Orion" or in equivalent terms. Sirius is the brightest star in the heavens; and the name is connected with the adjectives oetpos and amipcos, scorching. It may possibly be related to the Arabic Sird j, thus meaning the "glittering one." Hommel has shown that Sirius and Procyon were "the two Si'ray" or glitterers. It is doubtful whether Sirius is referred to in the Old Testament. By some it has been identified with the Hebrew mazzaroth, the Lu cifer of the Vulgate; by others with mazzalotji, the duodecim signa of the Vulgate; while Prof. M. A. Stern identifies it with the Hebrew kimah, which is rendered variously in the Vulgate as Arcturus, Hyades and Pleiades. (See G. Schiaparelli, Astronomy in the Old Testament [19o5].) The inhabitants of the Euphrates valley included both constellations in their stellar system ; but considerable difficulty is encountered in the allocation of the Bab ylonian names to the dominant stars. With the Egyptians Sirius assumed great importance. Appearing with the sun when the Nile was rising, Sirius was regarded as a herald of the waters which would overspread the land, renewing its fertility and promising good harvests for the coming season. Hephaestion records that from its aspect the rise of the water was foretold, and the Roman historian Florus adds that the weather was predicted also. Its rising marked the commencement of their new year, the annus canaries and annus cynicus of the Romans. It was the star of Sept or Sothis, and, according to one myth, was identified with the goddess Hathor—the Aphrodite of the Greeks. It was the "second sun" of the heavens, and according to Maspero (Dawn of Civilization, 1894) "Saha and Sopdit, Orion and Sirius, were the rulers of this mysterious world of night and stars." The Greeks, borrowing most of their astronomical knowledge from the Babylonians, held similar myths and ideas as to the constellations and stars. Sirius was named /ecp6e, Kuwv (the dog) and To ecarpov, the star; and its heliacal rising was associated with the coming of the dry, hot and sultry season. Hesiod tells us that "Sirius parches head and knees"; Homer speaks similarly, calling it rcaicov ri sa, the evil star, and the star of late summer (6sr pa) the rainy and stormy season. Procyon (Hporcvwv) was so named because it rose before Kvwv. The Euphratean myth of the dogs has its parallel in Greece, Sirius being the hound of the hunter Orion, and as recorded by Aratus always chasing the Hare; Pindar refers to the chase of Pleione, the mother of the Pleiades, by Orion and his dogs. Similarly Procyon became Maera, the dog of Icarius, when Bootes became Icarius and Virgo his daughter Erigone.
The Romans adopted the Greek ideas. They named the con stellation Canis, and Sirius was known as Canis also, and as Cani cula. Procyon became Antecanem and Antecanis, but these names did not come into general use. They named the hottest part of the year associated with the heliacal rising of Sirius the Dies cani culares, a phrase which has survived in the modern expression "dog-days"; and the pestilences which then prevailed occasioned the offering of sacrifices to placate this inimical star. Festus nar rates, in this connection, the sacrificing of red dogs at the feast of Floralia, and Ovid of a dog on the Robigalia. The experience of the ancient Greeks that Sirius rose with the sun as the latter entered Leo, i.e., the hottest part of the year, was accepted by the Romans with an entire disregard of the intervening time and a different latitude. (See SIRIUs.)