Sentence:  The Flute and Principal jump an octave at high pressures, while the <WSD>Quintade</WSD> can be heard at the 8' fundamental using low pressure on the cone-pallet box and can then overblow to the tierce at 90 mm WC. 
Meaning of the word marked with <WSD> tags:  An organ stop corresponding to pewter pipes of 16, 8, 4, and 2 feet.