is a name proper to one of the stars of the constellation canis major, called also simply the dog star; by the Greeks Σκύλης, Sirius. Canicula is the tenth in order in the Britannic catalogue; in Tycho's and Ptolemy's it is the second. It is situated in the mouth of the constellation; and is of the first magnitude, being the largest and brightest of all the stars in the heavens. From the rising of this star not cosmically, or with the sun, but heliacally, that is, its emersion from the sun's rays, which now happens about the 13th day of August, 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 annum canarium, 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 before the other stars, to compute their 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. Ephestion adds, that, from the aspect and colour of Canicula, the Egyptians drew prognostics concerning the rise of the Nile; and, according to Florus, predicted the future state of the year; so that the first rising of this star was annually observed with great attention.