Developments in Ceramic Materials Research

3.2. Wall-in Positions
The Use of Ceramic Pots in Old Worship Places 149
The method of use of medieval acoustic vases in Western Europe may be summarized as
follows: a) Areas of spaced vases in two or three rows inserted in stone walls of the interior
above ground level usually 2.5 m from the floor with their mouths opening inwards to the
nave or choir (e.g. St Clement’s, Kent). b) A single or double row of vases inserted in the
stone walls just bellow the ceiling, trusses or vault, often extending down the full length of
both side walls (e.g. St Nicolas, Leeds). c) At regular intervals across the stone barrel vaulting
of the choir (St Martin, Angers) d) In the sleeper walls bellow the choir stalls or in pits or
cavities (e.g. St Peter Mancroft, Norwich) [27].
The most common positions where the vases were found in Greek orthodox Churches
are: a) Dome crests. b) Niche crests. c) Bases of cylindrical domes and occasionally in the
inside part of the dome, d) Occasionally on the panel of the dome, e) Panels of antennas of
cross-shaped buildings, f) Cylindrical walls of triple-aisle churches, g) Irregularly positioned
in walls and occasionally in other kinds of domes [6]. A general observation is that,
depending on the architectural type of the church, a similar walling-in technique is
maintained, but the number of sound vases varies.
3.3. Ways of Walling-in
In Greece the following walling-in rules were followed systematically – regardless of the
period – with a very few, rare deviations [5].
Case a. With the spout-top of the vases facing the area of the temple: 65.8%.
Case b. With a perforated bottom facing the area of the church: 32.7%.
A percentage of 1.5%, cannot be determined due to their position.
The main axis of the vases is arranged vertically towards the wall surface and the opening
of the vase is on the same level with the plaster or directly below its thickness, usually visible.
When we have perforation of the bottom, the hole can have various shapes.
Mijic et al. discovered that only in a wooden church in Serbia, where vases have been
found, were they not build into the wall but instead were hanging freely in the attic space [1].
According to Kayili the resonators in Mosques were installed at the corners of joining
walls and ceiling, where critical points for normal modes of rooms are, especially for oblique
modes. [9, 10].