stage, assigned to Saturn, was blackened by means of a coating of bitumen spread over the face of the masonry; the second stage, assigned to Jupiter, obtained the appropriate orange color by means of a facing of burnt bricks of that hue; the third stage, that of Mars, was made blood-red by the use of half-burnt bricks formed of a bright red clay; the fourth stage, assigned to the Sun, appears to have been actually covered with thin plates of gold; the fifth, the stage of Venus, received a pale yellow tint from the employment of bricks of that hue; the sixth, the sphere of Mercury, was given an azure tint by vitrifaction, the whole stage having been subjected to an intense heat after it was erected, whereby the bricks composing it were converted into a mass of blue slag; the seventh stage, that of the Moon, was probably, like the fourth, coated with actual plates of metal.  Thus the building rose up in stripes of varied color, arranged almost as nature’s cunning arranges hues in the rainbow, tones of red coming first, succeeded by a broad stripe of yellow, the yellow being followed by blue.  Above this the glowing silvery summit melted into the bright sheen of the sky. [PLATE XVI.]

[Illustration:  PLATE XVI.]

The faces of the various stages were, as a general rule, flat and unbroken, unless it were by a stair or ascent, of which however there has been found no trace.  But there were two exceptions to this general plainness.  The basement stage was indented with a number of shallow squared recesses, which seem to have been intended for a decoration.  The face of the third stage was weak on account of its material, which was brick but half-burnt.  Here then the builders, not for ornament’s sake, but to strengthen their work, gave to the wall the support of a number of shallow buttresses.  They also departed from their usual practice, by substituting for the rigid perpendicular of the other faces a slight slope outwards for some distance from the base.  These arrangements, which are apparently part of the original work, and not remedies applied subsequently, imply considerable knowledge of architectural principles on the part of the builders, and no little ingenuity in turning architectural resources to account.

With respect to the shrine which was emplaced upon the topmost, or silver stage, little is definitely known.  It appears to have been of brick; and we may perhaps conclude from the analogy of the old Chaldaean shrines at the summits of towers, as well as from that of the Belus shrine at Babylon, that it was richly ornamented both within and without; but it is impossible to state anything as to the exact character of the ornamentation.