I recalled at once and distinctly the hot summer morning ten years back, when we had prepared that passage of the Eighteenth Book together in our study at Clifton; I at the table, Harry lolling in the cane-seated armchair with the Liddell and Scott open on his knees; outside, the sunny close and the fresh green of the lime-trees. Now that I looked more attentively the bare down, on which we climbed like flies, did indeed resemble a vast round shield, about the rim of which this unseen water echoed. And the resemblance grew more startling when, a mile or so farther on our way, as the grey dawn overtook us, Harry pointed upwards and ahead to a small boss or excrescence now lifting itself above the long curve of the horizon. At first I took it for a hummock or tumulus. Then, as the day whitened about us, I saw it to be a building--a tall, circular barrack not unlike the Colosseum. A question shaped itself on my lips, but something in Harry's manner forbade it. His gaze was bent steadily forward, and I kept my wonder to myself, and also the oppression of spirit which had now grown to something like physical torture. When first the great barrack broke into sight we must have been at least two miles distant. I kept my eyes fastened on it as we approached, and little by little made out the details of its architecture. From base to summit--which appeared to be roofless--six courses of many hundred arches ran around the building, one above the other; and between each pair a course, as it seemed, of plain worked stone, though I afterwards found it to be sculptured in low relief. The arches were cut in deep relief and backed with undressed stone. The lowest course of all, however, was quite plain, having neither arches nor frieze; but at intervals corresponding to the eight major points of the compass--so far as I who saw but one side of it could judge--pairs of gigantic stone figures supported archways pierced in the wall; or sluices, rather, since from every archway but one a full stream of water issued and poured down the sides of the hill. The one dry archway was that which faced us with open gate, and towards which Harry led the way; for oppression and terror now weighted my hand as with lead upon Grey Sultan's rein.