To many of our readers the words “Sothiac cycle” and “year of Sirius” will be but empty sounds. We will therefore give an explanation of them, in accordance with our promise to be intelligible even to the general reader. Let us adhere as closely as possible to the statement of Lepsius himself!--In the Egyptian heavens was visible a sidereal phenomenon which in a very remarkable manner corresponded perfectly, except for a mere trifle, to the Julian year of three hundred and sixty-five and a quarter days. It continued for more than three thousand years, and in fact was precisely coeval with the duration of the Egyptian empire. This was the heliacal rising of Sirius; that is, the reappearance of Sirius, the brightest fixed star, before sunrise. For a time this star was invisible, on account of its rising simultaneously with the sun. The early rise of which we speak occurred regularly one day later at the expiration of every four (civil) years of three hundred and sixty-five days, which was the simple basis on which the Egyptian calendar had been established at an early period. Thus when the New Year’s day of the fixed year of three hundred and sixty-five and a quarter days fell upon the first of the New Year’s month (Thot) of the civil year of three hundred and sixty-five days, then, after four fixed years, it fell upon the second of the New Year’s month, Thot, after 2 × 4 upon the third, after 3 × 4 upon the fourth of Thot, and so on. After 365 × 4, that is, when, after one thousand four hundred and sixty fixed years, it had run through all the days of the civil year, the next New Year’s day of the fixed year fell once more upon the first of the New Year’s month Thot, and the two forms of the year had thus readjusted themselves, so that one thousand, four hundred and sixty fixed years of three hundred and sixty-five and a quarter days were exactly equivalent to one thousand, four hundred and sixty-one civil years of three hundred and sixty-five days. We cannot here take cognizance of the slight error which resulted from the fact that the true solar year does not exactly amount to three hundred and sixty-five days and six hours, but only to three hundred and sixty-five days, five hours, forty-eight minutes and forty-eight seconds; nor can we now speak of the compensation therefor. In any case, it follows from what has been said that the Egyptians, during their whole history, had in their year of Sirius, computed according to the heliacal or early ascension of that star, the most perfect sidereal model ever possessed by any nation for their simple annual reckoning of the year of three hundred and sixty-five and a quarter days. Therefore Lepsius is right when he maintains that the Egyptians had a perfectly exact astronomical period in the Sothiac cycle of 4 × 365; that is, in the one thousand, four hundred and sixty years of Sirius, during which the civil year, shorter by a quarter of a day, readjusted itself by