This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1912 Excerpt: ...being attached to the tympanic membrane, one to the oval window, and the third lying between these two and jointed to each of them. What happens, then, is that sound vibrations in the air, entering the outer ear, strike on the tympanic membrane and set it into vibration, just as the disk of a telephone receiver is set ...
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This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1912 Excerpt: ...being attached to the tympanic membrane, one to the oval window, and the third lying between these two and jointed to each of them. What happens, then, is that sound vibrations in the air, entering the outer ear, strike on the tympanic membrane and set it into vibration, just as the disk of a telephone receiver is set into vibration by the sound striking on it; the membrane moves the bones, and the bones move the oval window and so transmit the vibration to the liquid of the inner ear. The difficulty of communicating vibrations from the air to the much heavier liquid of the inner ear is overcome by concentration and by leverage. The vibrations of the comparatively large tympanic membrane are communicated to the much smaller oval window and thus their force is concentrated. The leverage of the bones of the middle ear is such that the extent of movement is reduced in passing from the tympanic membrane to the oval window, and this helps to make it possible to set the liquid into motion. The second or round window between the middle and inner ear is necessary in order to permit the liquid in the inner to vibrate; for, since liquid is incompressible, the oval window would not be able to move inwards unless some other part of the wall of the inner ear moved outwards. The round window, opening back into the air of the middle ear, makes it possible for the oval window to move in and out and so communicate vibrations to the very small quantity of liquid in the inner ear. The middle ear, though filled with air, ' is separated from the air in the external ear by the tympanic membrane. How does the air get into the middle ear, and how is it renewed? There is a narrow tube, leading from the middle ear into the throat; it is called the Eustachian tube. By this roundabout ...
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Seller's Description:
Very Good. Inscribed by Woodworth! Gilt stamped maroon cloth boards, octavo, 359pp., not illustrated. Book VG with mild rubbing and cornerwear to boards and spine, gentle bumps to corners, binding tight, text clean and unmarked. No DJ.