|Ø ext.||External diameter|
|Ø int.||Internal diameter|
|NS||Normal Scale (according to Töpfer Index).|
All measurements are in millimetres unless otherwise stated. Stop names are designated as they appear on the stop labels.
|Nicking on the languid is shown as:|
|Nicking on the lower lip is shown as:|
Similarly, where a difference in the thickness of wood occurs, the thickness of the side into which the mouth is cut is shown first. e.g. 6 x 7 would mean that the side into which the mouth is cut has thickness of 6mm.
|1. "no ears". The sides of the mouth have been completely cut away so that no "ears"are present.|
|2. "half ears". The sides of the mouth have been bevelled, so that only half "ears" remain.|
|3. "level ears". The sides of the mouth are left untouched, leaving "ears" level with the pipe body.|
|4. "protruding ears". Ears have been added to the sides of the mouth.|
|5. "inverted mouth". The pipe is of such a construction that there is no bevel present on the external surface of the upper lip.|
It was found that this aim was best fulfilled when the internal diameters of the pipes constituting such a rank were halved at every 17th note. Thus, a standard measurement was adopted for any pipe of any length. This measurement defined the internal diameter that pipe should have in order for the mathematical and scientific principles of pipe construction to be followed. This standard was called Normal Scale, and any pipe of a particular length having the internal diameter suggested by the Töpfer Index is said to have Normal Scale (NS). However, if a pipe of a particular length has the internal diameter of the next smallest pipe on the Töpfer Index, it is defined as having a scale of -1.
* P.G. Andersen: Organ Building and Design, Allen & Unwin, 1969, p58.