Plans of tholobate, dome and lantern taken at different levels, engraving from The Vatican and...

Plans of the tholobate, the Dome and the Lantern taken at different levels: N 1, Plan from the octagonal base of the tholobate; N 2, plan at the level of the external pedestals of the tholobate; N 3, Plan from the base of the interior and exterior columns of the tholobate; N 4, Plan from top the interior and exterior trabeated order of the tholobate; N 5, Plan from top the springer of the dome; N 6, Plan at the summit of the dome and the springer of the lantern; N 7, Plan of the top of the buttresses of the lantern; N 8, Plan at the summit of the lantern and the level of the sphere, engraving from The Vatican and St Peter's Basilica, 1882, by Paul Marie Letarouilly (1795-1855), Volume I, St Peter's Basilica, Plate 21. Paris, Bibliothèque De L'Institut De France