Ramsay
"The contraction and expansion of the air in one vibration is effected in successive times; but the compression of the air of one vibration and the expansion of the air of the preceding one are simultaneous, so they" [Scientific Basis and Build of Music, page 23]

See Also

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5.8.5 - The complete Contraction Expansion Cycle is as follows
13.22 - Contraction Expansion
9.27 - Expansion and Contraction
17.08.01 - Gravitation and Radiation Keely
Law of Assimilation
Ramsay - The New Way of Reckoning a Vibration