be seen by all passers-by, is a rectangular block of porphyry, thirteen feet one inch square and three feet three inches thick, and of the enormous estimated weight of twenty-four tons. The sculptured portion of the block, on the exposed face, is contained in a circle, eleven feet one inch and four-fifths of an inch in diameter. The regularity and geometrical precision with which the figures are executed called forth enthusiastic admiration from Humboldt, and has been the source of equal wonderment to many later observers. Our cut is a reproduction of Charnay’s photograph, by means of the photo-engraving process, and may be relied upon as absolutely correct. Prescott considers that the original weight of the block before it was mutilated must have been nearly fifty tons; and as no similar stone is found within a radius of twenty-five miles of Mexico, that it must have been brought from the mountains beyond Lake Chalco.[583] Some remarks upon the Aztec calendar will be found in the following chapter. The sacrificial stone is a cylindrical block of porphyry, nine feet ten inches in diameter and three feet seven inches thick, and is now lying in the courtyard of the University of Mexico. If the reader will imagine the border of the calendar-stone outside of the eight triangular points removed entirely, will substitute a concave basin in the place of the central face or sun, also instead of all the calendar signs intervening between the face and the circle, upon which the base of the four principal triangular figures rest, will imagine the existence of several concentric circles not unlike strings of beads, he will have a general idea of the top of the stone. We should not omit to state that a groove or channel leads from the central basin to the outer circumference. The use of the stone is a matter of controversy, Humboldt considering it the gladiatorial stone, Gama a calendar-stone, and Tylor that it was an altar on which animals were sacrificed. Fifteen groups of two human figures, each dressed in the insignia of royalty, are sculptured around its circumference. Bancroft, as well as several others, give cuts of the stone and sculptures. The horrid monster Teoyaomiqui—goddess of death—is sculptured in high-relief on a block of porphyry ten feet high and six feet wide and thick. Probably no mythology nor all the mythologies of the world besides could produce so hideous and unsightly a combination of reptile, human and infernal forms, as make up the three sides of this idol.[584] Mr. Bancroft first figured the beautiful earthen burial vase dug up in the Plaza Tlatelulco and sketched by Col. Mayer. It is twenty-two inches high and fifteen and a half inches in diameter; a closely fitting lid most chastely sculptured covered it, as will be seen in the accompanying cut. [Illustration: Aztec Calendar Stone in its Present Condition.] [Illustration: Burial Urn from Mexico.]