Tousoun Pasha, left by his father Aly as governor of Arabia, concluded, in June, 1815, a treaty of peace with the Wahabi. The possession of the whole desert and the far greater part of the Bedouin tribes were given up to them, while the holy cities with their territories were acknowledged as dependencies of the Sultan. The Wahabi promised to put no obstacles in the way of the great pilgrim caravans. But it is contrary to the politics of Mohammed Aly to quell that war entirely, for he knows that as long as Arabia is in an unsettled state, and Mekka in danger, he becomes necessary to the Mussulman world in his governorship of Egypt, of which he might possibly be soon deprived if the Hedjaz was quiet; he has therefore refused to ratify the treaty, and his younger son, Ibrahim Pasha, is now proceeding to Arabia with a new armament of troops. The expenses of the war are covered by the income of Djidda and the great profits accruing to the Pasha from his monopolies in the trade of the Arabian coast. A lucky chance has put me in possession of very interesting papers concerning this Wahabi war, which together with the information I collected in the Hedjaz, will enable me to throw considerable light upon the whole Wahabi sect and their affairs. For three successive years the plague has raged at Cairo, and great apprehensions are entertained of its return this spring. If it be so I shall neither imitate my Mussulman neighbours in taking no precaution whatever against its attacks, nor the Greeks and Franks who shut themselves up for three or four months in their houses as close prisoners; but I shall leave the infected borders of the Nile, and seek for refuge among the Bedouins. As I have at present completely recovered my health, which I principally ascribe to an excursion through the Delta, after my visit to Alexandria, I do not despair, provided my health keeps pace with my spirits for the next three or four years, to bring my labours to a successful completion.