The first water-jacketed cupola which came into general use was a circular inverted cone, with a slight taper, of 36 inches diameter at the tuyeres, and composed of an outer and an inner metal shell, between which water circulated.
Shut out, in spite of the deserved success of his decorations of the cupola of Val de Grace (1664), from any great share in those public works the control of which was the attribute of the new Academy, Mignard was chiefly active in portraiture.
The style is Gothic, very elaborately decorated, but it shows many peculiarities, for the work was continued through several centuries and after many designs by many masters, notably by Amadeo, who carried out the octagonal cupola (the pinnacle of which dates from 1774), and by Tibaldi, who laid down the pavement and designed a baroque facade.
His principal architect was Domenico Fontana, who, in conjunction with Guglielmo della Porta, completed the uniquely beautiful cupola of St Peter's which had already been designed by Michelangelo in a detailed model.
In the very earliest submarines a cupola was built on the top of the hull, which was kept just above the surface when it was desired to take observations.
It is noteworthy for a splendid ruined mosque built by the Seljuk, Isa Bey II., of Aidin, in 13 7 5, which contains magnificent columns: for a castle, near which lie remains of the pendentives from the cupola of the great cathedral of St John, now deeply buried in its own ruins: and for an aqueduct, Turkish baths and mosque-tombs.
Internally it is a polygon of sixteen unequal sides, and the cupola is supported by sixteen ribs, springing from the same number of columns.
In a very few places the molten cast iron as it issues from the blast furnace is cast directly in these moulds, but in general it is allowed to solidify in pigs, and then remelted either in cupola furnaces or in air furnaces.
The cupola furnace (fig.
Eggert in the Florentine Renaissance style, was built in 1889-1893; it is crowned by a cupola 115 ft.