star in the constellation Canis Major, called also Sirius or the Dog-star. It is situated in the mouth of the constellation, and is of the first magnitude, being the largest and brightest of all the fixed stars. From the rising of this star heliacally, that is, its emission from the sun's rays, the ancients reckoned their dies canicularis, or dog-days. The Egyptians and Ethiopians began their year at the rising of the canicula, reckoning to its rise again the next year, which is called annus canarius or canicular year. This year consisted ordinarily of 365 days, and every fourth year of 366, by which it was accommodated to the civil year. The reason of their choice of the canicula to compute time by was, not only the superior brightness of that star, but because its heliacal rising was in Egypt a time of singular note, as falling on the greatest augmentation of the Nile, the reputed father of Egypt. Hephaestion adds, that from the aspect and colour of the canicula the Egyptians drew prognostics concerning the rise of the Nile; and according to Florus, they predicted the future state of the year; so that the first rising of this star was annually observed with great attention.