To measure a wall would not seem to be a complicated business, yet I do not care to remember how many hours I spent upon the mosque. Its great size is no advantage when seen over the edge of a metre tape, and the action of the wind upon its masonry has been fatal to accuracy. The face of the brick is destroyed higher than a man can reach by the constant scrub and wear of the heavier sorts of desert dust, which makes the exact noting of angles exceedingly difficult. The buildings on the west bank of the river, among which I spent the two succeeding days, were even more disfigured, and the palace of the khalifs, except for its three vaulted halls, a crowning confusion of mounds and rock-cut subterranean chambers. It was not until I had made acquaintance with all these that I found time to visit the modern town. I had been spending a few final hours in the great mosque and was beginning to wonder whether a metre tape and a camera are advantageous additions to the equipment of travel, a doubt which was shared by the zaptieh and Jûsef, whose duty it was to stretch the one and carry the other over weary acres of crumbling ruin. When at last we turned our horses’ heads to the little town lying out upon the plain, we felt that there was a great deal to be said for prejudices which forbid the measuring and photographing of mosques that cover the bones of saints. The town walls have recently been rebuilt, for the acquisition of merit, by a pious Persian; he neglected, however, to turn his attention to that which they enclose, and the first few hundred yards of sacred Sâmarrâ is a vacant desolation, the home of dust and dirt. Having crossed this area we plunged into mean and narrow streets. All the windows facing outwards had been blocked up, and within or without there was no living soul to be seen as we rode down the silent ways. But when we drew near the mosque we became aware that Sâmarrâ was not quite uninhabited. Grave Persians and ragged Arabs sat at the tea-shops before the gateway; they gave me the salute as I passed, and I was careful not to gaze too curiously through the arch where the big chain hangs across the entrance of the shrine. Inside, under a dome of priceless tiles, are the tombs of the tenth and eleventh Shî’ah Imâms, while the smaller dome of gold covers the cleft into which vanished the Mahdî, who will appear again when the time is ripe. Therefore when you see black ensigns, black ensigns coming out of the east, then go forth and join them; for the Imâm of God will be with those standards, and he will fill the world with equity and justice.