Tyndall, John, 1820-1893 · New York : Appleton · leaf 379
feeble motion) of the sandis perceived. Placing the ends of the two branches overalternate sectors of the disk, the sand is tossed from themembrane, proving that in this case we have coincidenceof vibration on the part of the two sectors. We are now prepared for a very instructive experi-ment,… … INTENSITY AUGMENTED BY PARTIAL EXTINCTION. 371 uiinished. is augmented. When two hands are placed over two adjacent sectors, you notice no increase ofthe sound; but when they are placed over alternate 159, a striking augmentation of the sectors, as in Fig. Fig. 169. sound is the consequence.By…
Sound
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