The exterior of this interesting edifice is singularly heavy, and, as a celebrated French traveller says, _furieusement lourde en dehors_. It exhibits an irregular mass of cupolas, half-domes, shelving roofs, and stunted minarets; one of which, more mean than the rest, is the identical one erected by Mahomet to convert the church into a mosque. Even the great dome, so celebrated for its architectural beauty, and which the Turks have never yet been able to imitate, looks low and flat when viewed on the outside, and produces nothing of that “aërial” effect, in comparison to its internal structure. The edifice has at length begun to exhibit symptoms of decay. About six years ago, after a continued storm of wind and rain, one of the smaller domes fell into the church. On clearing away the surface of rubbish, the flooring was found covered over with glittering cubes which had formed the ceiling, and, in such abundance, that every one was supplied with as much as he chose to take for a trifling gratuity. The Turks regard this mosque with a veneration and jealousy greater than any other. It is not always difficult to obtain admission to the rest, and generally the area in which they are placed is a thoroughfare, through which a Frank may pass unmolested, but the foot of an infidel is never suffered to desecrate, a second time, the precincts of this converted temple: if he attempt to approach, he is always driven back with abuse. The only occasion when permission is given to see it, is when an ambassador arrives, or is about to leave Constantinople. As a special favour, a firman is granted to him and a certain number of his suite, who are then, only, permitted to enter without molestation. But even this is not always a protection against the fanaticism of individuals. Secretaries to embassies, accompanied by their ladies, have been insulted and assaulted with the sultan’s firman in their hands. [Ilustration: T. Allom. G. Presbury. EYOUB SULTAN,--FOUNTAIN AND STREET OF TOMBS.]