and young children, were made to assume masks of maguey leaves, and the former were shut up in the granaries. It was feared that women in this condition might become monsters and devour their relations, and that the children might be turned into mice, especially if they were allowed to fall asleep. New fire was also made at the dedication of a new temple, or the completion of a new house. The employment by the Mexicans of a solar year of 365 days brings us to the question whether they at any time intercalated any day or days to make their year square with real solar time. It is quite obvious that a people, most of whose feasts were connected with agriculture, were bound to notice that their festivals gradually failed to correspond with the seasons, and many conjectures have been made regarding the methods which they might have used to rectify their calendar. It must be confessed however that there is no direct evidence that days were ever intercalated in the latter, and Seler has shown that at any rate between the year of the conquest, and the date of Sahagun’s writing, some forty years, no intercalation had been made. Moreover the confusion into which the calendar had fallen at the beginning of the sixteenth century seems to be evidence against the practice. It is quite possible that when the discrepancy became too great a new start was made, and it may be that the five “suns” typifying the five ages of the world really represent five attempts to establish a calendar. The sun was not the only body the observation of which served as a check upon the calendar. The planet Venus was also of the greatest importance, and its synodical revolution was closely connected with the 104-year period which constituted the longer cycle of the Mexicans. This revolution occupies practically 584 days, and consequently five such revolutions are equal to eight years of 365 days. Since 20 when divided into 584 leaves a remainder of 4, it is obvious that the commencement of a Venus-period will fall always on one of five of the twenty day-signs. Further, since 13 when divided into 584 leaves a remainder of 12, it is equally obvious that each successive Venus-period will open with a day of which the numerical sign is one less than that of the preceding period. In several of the MSS. we have the Venus-periods set out in the order in which they occur, viz. on the days cipactli, coatl, atl, acatl and olin; 1. cipactli being followed by 13. coatl, the latter by 12. atl, and so forth. It can be seen that 65 Venus-periods must elapse before the same sign occurs in conjunction with the same number at the commencement of a period, and this amounts to 104 years of 365 days, viz. the longer cycle of the Mexicans. It seems most probable that the Venus-period was utilized as a means of correcting the 365-day year, and I am even inclined to believe that observation of this planet was practised before the institution of the solar calendar.