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. 1871 Excerpt: ... the atmosphere without becomes greater or less than that within, the tympanum feels the strain, pain is experienced, and partial deafness ensues. A forcible concussion frequently produces in this way a temporary deafness. In the act of swallowing, the tube is opened and the equilibrium restored. We may force air into ...
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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. 1871 Excerpt: ... the atmosphere without becomes greater or less than that within, the tympanum feels the strain, pain is experienced, and partial deafness ensues. A forcible concussion frequently produces in this way a temporary deafness. In the act of swallowing, the tube is opened and the equilibrium restored. We may force air into the cavity of the ear by closing our mouth and nose, and forcibly expiring the air from our lungs. This will render us insensible to low sounds, as the rumble of a railway-train, while we can hear the higher ones as usual. Limits Of Hearing.--Helmholtz fixes the lowest limit of musical sounds at 16 vibrations per second, and the highest at 38,000. Below this number the pulses cease to link themselves together, and become distinct sounds. The range of the ear is thus about eleven octaves. The practical range of music is, however, only about seven octaves. The capacity to hear the higher tones varies in different persons. A sound which is entirely audible to one may be utter silence to another. Some ears cannot distinguish the squeak of a bat or the chirp of a cricket, while others are acutely sensitive to these shrill sounds. Indeed, the auditory nerve seems generally more alive to the short quick vibrations than to the long slow ones. The whirr of a locust is much more noticeable than the sighing of the wind through the trees. To this, however, there are noticeable exceptions. The author knows of a person who is entirely insensible to the higher tones of the voice, but acutely sensitive to all the lower ones. Thus on one occasion, being in a distant room, she did not notice the ringing of the bell announcing dinner, but heard the noise the bell made when returned A tone produced by about 32 vibrations per second may be made by inserting the fi...
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Add this copy of Fourteen Weeks in Natural Physiology to cart. $63.43, good condition, Sold by Bonita rated 4.0 out of 5 stars, ships from Newport Coast, CA, UNITED STATES, published 2010 by Nabu Press.
