distances by enormous buttresses. These resembled towers without parapets, overlooking every part of the encircling road, and from them the defenders could take the attacking sappers in flank. [Illustration: 351.jpg THE RAPIDS OF THE NILE AT SEMNEH, AND THE TWO FORTRESSES BUILT BY USIRTASEN III] Map drawn up by Thuillier from the somewhat obsolete survey of Cailliaud The intervals between them had been so calculated as to enable the archers to sweep the intervening space with their arrows. The main building is of crude brick, with beams laid horizontally between; the base of the external rampart is nearly vertical, while the upper part forms an angle of some seventy degrees with the horizon, making the scaling of it, if not impossible, at least very difficult. Each of the enclosing walls of the two fortresses surrounded a town complete in itself, with temples dedicated to their founders and to the Nubian deities, as well as numerous habitations, now in ruins. The sudden widening of the river immediately to the south of the rapids made a kind of natural roadstead, where the Egyptian squadron could lie without danger on the eve of a campaign against Ethiopia; the galiots of the negroes there awaited permission to sail below the rapids, and to enter Egypt with their cargoes. At once a military station and a river custom-house, Semneh was the necessary bulwark of the new Egypt, and Usirtasen III. emphatically proclaimed the fact, in two decrees, which he set up there for the edification of posterity. “Here is,” so runs the first, “the southern boundary fixed in the year VIII. under his Holiness of Khâkerî, Usirtasen, who gives life always and for ever, in order that none of the black peoples may cross it from above, except only for the transport of animals, oxen, goats, and sheep belonging to them.” The edict of the year XVI. reiterates the prohibition of the year VIII., and adds that “His Majesty caused his own statue to be erected at the landmarks which he himself had set up.” The beds of the first and second cataracts were then less worn away than they are now; they are therefore more efficacious in keeping back the water and forcing it to rise to a higher level above. The cataracts acted as indicators of the inundation, and if their daily rise and fall were studied, it was possible to announce to the dwellers on the banks lower down the river the progress and probable results of the flood. [Illustration: 353.jpg THE CHANNEL OF THE NILE BETWEEN THE TWO FORTRESSES OF SEMNEH AND KUMMEH] Reproduction by Faucher-Gudin of a sketch published by Cailliaud, _Voyage à Méroe, Atlas_, vol. ii. pl. xxx.