Thirty-Fifth, Flatted English

Listed only by Irwin, who says:

A rank of Foundation pipes that is pitched at 2/7' on the manuals, and 4/7' on the pedals. This is at the note four octaves and a flatted seventh above the key depressed. Since this rank sounds only in the vicinity of the twenty-eighth harmonic, it will only partly corroborate its pitch, assuming combination with a unison stop. It speaks two octaves above the 1-1/7' Septième on the manuals, and two octaves above the 2-2/7' Septième on the pedalboard. It is of use in some mixtures, but much too high for a mutation stop. From middle C it would speak at Bb5; from the pedal's low CCC key it speaks Bb2.

Irwin is incorrect. A properly tuned 2/7' rank will, in fact, speak precisely at the 28th harmonic of the 8' series. In an equally-tempered instrument this harmonic sounds only roughly at Bb, not exactly; a rank tuned to speak precisely at Bb would be practically useless.

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