diameter at the 17th note but is somewhat wider could be described as "+ 2 ht" meaning that the pipe corresponding to the note "D" has the width expected for a pipe of the note "C", two semitones below (and therefore two semitone intervals wider). If a rank does not halve exactly at the 17th note, then its relationship to the Normalmensur will vary across the keyboard. The system can therefore be used to produce Normalmensur variation tables or line graphs for the analysis of existing ranks or the design of new ranks. The following is a list of representative 8′ stops in order of increasing diameter (and, therefore, of increasingly fundamental tone) at middle C with respect to Normalmensur, which is listed in the middle. Deviations from Normalmensur are provided after the pipe measurement in brackets. Viole d'orchestre (thin, mordant string stop): 35.6 mm [-10 ht] Salicional (broader-toned, non-imitative string stop): 40.6 mm [-7 ht] Violin diapason (thin-toned principal stop): 46.2 mm [-4 ht] Principal (typical mid-scale principal stop): 50.4 mm [-2 ht] Normalmensur: 54.9 mm [+/-0 ht] Open diapason (broader-toned principal stop): 57.4 mm [+1 ht] Gedeckt (thin-toned flute stop): 65.4 mm [+4 ht] Flûte à cheminée (typical mid-scale flute stop): 74.4 mm [+7 ht] Flûte ouverte (broader-toned flute stop): 81.1 mm [+9 ht] Normalmensur scaling table, 17th halving ratio: From Organ Supply Industries catalog External links Calculs de tailles de tuyaux d'orgues, 'L'Hydraule' (in French) References Pipe organ components