become much silted up. In 1828 this gateway was in a sad state of decay, but it was then attended to, and the upper part of the exterior built up and plastered over; this naturally rather spoils the effect. The inside is as beautiful as ever, although some of the sandstone is flaking away with age. The diaper ornamentation ceases abruptly at the level of the commencement of the dome, but this leads the eye to notice the very effective pendentive arches by which the corners are spanned and the square building is brought to an octagonal shape : these arches are of a horseshoe form. At the angles of the octagon are brackets, which support the next course (which is circular) where it projects in- wards, and thus the square is brought to a circle of a diameter of thirty-three feet. The walls are eleven feet in thickness.
Tomb of the Imam Zamin. — It is interesting to notice what measures were adopted in forming the circular dome above this square building, which dates some two hundred and thirty years later than the Alai Gate. Here the octagon is formed by lintels across the corners of the main walls, and the outside of the dome, up to the cornice, is octagonal, instead of a circular dome starting from a square roof, as in the case of the gateway.
