over Churches and similar Spaces. 239 



this kind, so far as the author is aware, exists in the church of 

 Niederbriessig on the Rhine, a building of the year 1718. 

 Another opportunity must be taken of describing how the 

 author was so fortunate as to be able to vault two churches of 

 his own building with solid stone how what has here been 

 said was applied in practice and how so many other difficul- 

 ties of all kinds which occurred were happily obviated. In the 

 mean time a hasty statement of the dimensions may serve to 

 shew the applicability of this mode of vaulting in all cases. 

 The greater of these churches, which is entirely in the pointed- 

 arch style, js, in the clear, 57 feet wide and 48 feet high, is 

 divided by two rows of pillars, 17 feet from axis to axis, 3 feet 

 thick, and 25 feet high, into a middle-nave of 30 feet clear, 

 and two aisles ; and is vaulted over with pointed cross- vaulting 

 of the sandstone above described, and with intermediate ribs 

 of only 6 inches thick. All the centerings under this vault are 

 of wood from 4 inches to at most 5 inches scantling. The 

 greatest of these did not in any case consist of entire arches, 

 but only of segmental arches fastened together. The outer 

 walls, executed in irregular broken stones, are 3 feet thick, 50 

 feet high, and are strengthened by buttresses of the same thick- 

 ness, separate 17 feet from one another, projecting 4 feet, and 

 having a height of 30 feet. The tower, 21 \ feet square, and 

 in the wall-work 110 feet high, carries an octagonal spire 124 

 feet high, built of wood and covered with slates. 



In the small church, in the round arch style, the buttresses are 

 in the interior, and are rounded into niches. The interval of these 

 is also 17 feet, and the breadth of the middle-nave, between the 

 pillars (which are 2 feet thick and 22 feet high) is 22J feet ; 

 the whole clear breadth between the buttresses is 42 feet. The 

 pillars and walls are bound together both in a longitudinal and 

 transverse direction by semicircular ribs, and the compartments 

 thus formed are covered with cupola ceilings 6 feet thick, which 

 were vaulted freehanded, without any mechanical assistance. 



At a later period, on the occasion of the vaulting of the 

 choir in another church, with a similar cupola of 24 feet square, 

 there occurred to the author a simple method of preserving the 

 complete accuracy of the form of the cupola. He caused a 

 very light pole, of the length of half the diagonal, and conse- 



R 2 



