The most important analysis of this sanctuary was undertaken by Eric Schroder. He identified the use of two systems of the proportion known as the Golden Section. This was achieved by the construction of a pentagon which has the property that the line connecting two opposite points cuts the perpendicular dropped from the intermediate one in such a way that the golden section is formed. The golden section is that point on a line which has been unevenly divided into two at which the proportion between the larger and smaller divisions is the same as that between the whole line and the larger division.

In the drawing above I have imposed Shroder's plan of the setting up on the outside of the chamber, and although the alignment is nor exact because of the angle from which the picture has been taken, the relationship of key structural components to this proportion is fairly clear.

"The total inner height is twice the base and this total height is divided at Zeising's 'Golden Section' in such a way that the lesser part is below ... The peak of the lower main arch is at Zeising's section of the height of the great octagon arch which surmounts it ... Since it is the property of the pentagon that a perpendicular from the apex to the base is divided at its Golden Section by a line joining the remaining angles, the pentagon in the dome interior must be taken as the architect's symbol of the ratio, which he has twice employed."The architect was perfectly aware of what he was doing and the roof incorporates a pentacle in the insider as if to give a clue to the tranquil effect he has evoked.

Eric Schroeder