"The _façades_ of the building are of very simple, yet bold and effective design; and, with the exception of the cornice, but few projections are introduced. The fronts in Thames-street and St. Mary's-at-hill are respectively about 112 feet in width by 61 feet in height. The unequal form of the plot of ground on which the Exchange stands is skilfully masked at the corner by breaking the mass of building, and introducing a circular tower in the re-entering angle, within which is the entrance vestibule. This circular tower is 109 feet to the top of the gilded ball, and 22 feet in diameter at the lowest part, and is divided into three stories. The lowest story, containing the vestibule, is of the Roman-Doric style of architecture; and there is a striking peculiarity in the arrangement of this part, to which we must advert. The wall of the tower not only shrines the vestibule by which entrance to the hall or Rotunda is attained, but serves also as a centre to flights of steps, which lead, on either hand, to a landing on the first story of the building, and thence a spiral staircase is carried up in the tower to the other stories. The first story is of the Ionic order, carrying an entablature, and is lighted by windows. The top story, fifteen feet in diameter, is ornamented by pilasters, with windows between--the roof rising to a cone, and being crowned with a gilded ball. This is, to our view, the least successful portion of the edifice, the termination being stiff, and not so piquant as it should have been. We should mention, the exterior is of Portland stone.