242

HISTORY OF ENGINEERING.

Book I.

decorated ; externally, the lowest is of the Doric , the second the Ionic , the third theCorinthian , and the uppermost or lantern of the Composite order.

On the ground or lower floor is a vaulted hall, the dimensions of which are 22feet square, and the height 20 feet; it contained two wardrobes, and many other conve-niences obtained out of the thickness of the walls.

Over this is the grand saloon 21 feet square, and 20 feet in height, a vestibule, twowardrobes, and other conveniences, the whole vaulted with flat elliptical arches.

The third story was appropriated to the chapel, which was of a circular form, coveredwith a dome; the internal diameter was 31 feet, and the height, including the hemi-spherical dome, 40 feet. The interior was decorated with paintings and mosaic; the lightwas admitted through eight windows, and in the centre was a circular opening 4 iletdiameter, protected by a balustrade.

elevation

THE LIGHTHOUSE.

The diameter of the lantern, which formed the third story, is 14 feet, and around theexterior is a stone balcony, the internal diameter of which is 21 feet, forming a solidcovering to the chapel below it. On the outside are eight Corinthian pilasters, whichanswer to the mullions, between which are as many glazed windows, 2 feet 6 inches wide,and 7 feet high.

The inside of this story is 20 feet in height up to the square, which is covered by a hemi-spherical cupola, making its whole height 27 feet; this cupola, which is formed withstone, and built very solidly, serves as a basement to the lantern, originally 5 feetdiameter internally, and 9 feet externally, and the height above the cupola 17 feet; in themiddle was an opening 18 inches diameter; through this the smoke passed into a smallerfunnel, 2 feet 6 inches diameter, in which were a number of small holes that allowed itsescape. The upper funnel or turret was capped with solid stone, 31 feet above the floor ofthe lantern light.