The triumphal arch of Constantine, which occupies the centre between the two marble towers, conducts to the golden gate in the exterior enclosure of the castle. The arch was more than ninety feet in height; but it has been so much injured by artillery, that no idea can now be formed of its ornaments. In the second marble tower is the _Cave of Blood_: the first door by which it is entered is of wood; this opens into a corridor of twelve feet long by four feet wide, having at the end two iron steps ascending to an iron door, and this leads into a semicircular gallery; at its furthest extremity is a second iron door, which completes the gallery, and ten feet further an immense massive door enclosing the dungeon. In the midst of this sarcophagus is a well, the mouth of which is level with the ground, and half closed by two flag-stones; to this is given the name of the _well of blood_, because the heads of those who are executed in the dungeon are thrown into it. In the same tower with this dungeon is a staircase leading up to a number of cells; from some of them, which are higher than the ramparts, the eye may be gratified with a view over Constantinople through loop-holes pierced in the walls. Here the Turks formerly used to confine those whom they call _mouzafirs_, or hostages; but the latter have now the choice allowed them of hiring more eligible apartments. The first enclosure of the Seven Towers is inhabited chiefly by poor Turks, who have houses, and live there with their families. They also belong to the guard of the castle. The air of the Seven Towers is in general unwholesome, and very likely to produce scrofula. In the summer the walls, heated by the sun, transform the place into a furnace; and the apartments on the first floor are at all times extremely damp. Our engraving, aided by the subjoined references, will, however, enable our readers to form an accurate idea of the topography of the _Seven Towers_. It is copied from the Travels of M. Ponqueville, who devotes a chapter of his quarto volume to a minute description of towers, gardens, and fortresses. Nothing can exceed the horror with which his catalogue of their miseries is calculated to impress the reader; indeed, they fall but little short of some of the highly-wrought fictions of barbarous romance. * * * * * ASTRONOMICAL OCCURRENCES FOR DECEMBER, 1827. (For the Mirror.) The sun enters the cardinal and tropical sign _Capricorn_ on the 22nd, attaining his greatest austral declination at 1h. 31m. afternoon. The moon is in opposition on the 3rd; in apogee on the 6th, and in conjunction and perigee on the 18th. Mercury is in perihelion on the 1st, becomes stationary on the 9th, and reaches his greatest elongation on the 19th, when he may be seen before sunrise, as well as a few preceding and succeeding mornings; be rises on the abovementioned day at 6h. 8m.