Tyndall, John, 1820-1893 · New York : Appleton · leaf 183
received thieaccession. 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 one risesthe middle segment of the other falls—what would be theconsequence of adding them together? Evidently a… … letter p means positive, inuieating, in the section wnere itoccurs, a motion of the plate upward ; while n means nega-tive, indicating, where it occurs, a motion downward. Youhave now before you a kind of check pattern, as shown inthe third square, consisting of a square s in the middle, asmaller…
Sound
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