Tyndall, John, 1820-1893 · London : Longmans, Green · leaf 167
which has received thisaccession. But suppose the vibrations of the two plates,instead of being concurrent, to be in exact opposition toeach other that when the middle segment of the onerises the middle segment of the other falls—what wouldbe the consequence of adding them together ? Evidentlya… … letter P means positive, indicating, in the section where itoccurs, a motion of the plate upwards ; while N meansnegative, indicating, where it occurs, a motion downwards.You have now before you a kind of check pattern, as shownin the third square, consisting of a square s in the middle,a smaller…
Sound
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