The Cambridge History of India, Vol. IV: The Mughul Period v4.c23.s4.168.4

v4.c23.s4.168.4

In the interior, except for the wooden pavilion in the centre under which the cenotaph is placed, the only other noticeable features in this great bare hall are the tall pointed arches supporting the dome. And in the arrangement of these arches the builder showed his consummate skill in solving a difficult problem of construction in a scientific and at the same time artistic manner. The intention of the building required him to lay out the foundations of the hall on a square plan, and, as the walls gained height, gradually to change this square so that the summit of the walls finished in a circle; on this circular cornice he could readily construct his dome. By an ingenious combination of eight intersecting arches, the foot of each standing within the square plan but its plane set at an angle, the corner was bridged over, the whole construction eventually forming a broad circular gallery or platform of masonry some 24 feet wide and more than 100 feet from the ground. With this platform as a base the builders proceeded to erect the huge inverted bowl of the dome. The materials used for this purpose were bricks and mortar, and a noticeable fact is the great thickness of the mortar between each course, so much so that the dome may be described as consisting of a hollow mass of concrete reinforced with layers of brick set in level courses.