. Natural philosophy. including statics, hydrostatics, pneumatics, dynamics, hydrodynamics, the general theory of undulations, the science of sound, the mechanical theory of music, etc. : designed for the use of normal and grammar schools, and the higher classes in common schools . tivated his voice, so as to reach through three oc-taves. The entire range of the human voice, taking both male and femaletogether, may be said to be about four octaves. 436. Birds have a true larynx whicJi is often very complex, and which is placed at the lower extremity of thetrachea, just where it branches into t
. Natural philosophy. including statics, hydrostatics, pneumatics, dynamics, hydrodynamics, the general theory of undulations, the science of sound, the mechanical theory of music, etc. : designed for the use of normal and grammar schools, and the higher classes in common schools . tivated his voice, so as to reach through three oc-taves. The entire range of the human voice, taking both male and femaletogether, may be said to be about four octaves. 436. Birds have a true larynx whicJi is often very complex, and which is placed at the lower extremity of thetrachea, just where it branches into the bronchial upper end of the trachea opens into the pharynx by amere slit. Birds in which the true or lower larynx is ab-sent, are necessarily voiceless. In the cat the upper andlower vocal cords are almost equally developed, and hencethe variety and range of its voice. The horse and ass have 437 THE ORGANS OF HEARING. 181 only two vocal cords. The sounds produced by insects arecaused by percussion or by rubbing the homy sheaths oftheir wings or legs together, or by the rapid vibrations oftheir wings or by the contraction and expansion of theirair tubes, which forces the air through their orifices so asto make it whistle. • THE ORGANS OF VERTICAL SBCTIOX OF THE ORGAX OF HEAEIXO. 437. The organ of hearing in man is composed ofthree parts, viz. :— I. The External Ear or The Middle Ear or The Internal Ear or Labyrinth:— 438. The External Ear consists of two parts. I. The Pinna or Pavilion («6c), also called the ala orwing and the auricula. II. The Meatus AucUtorius, or auditor canal (d). Boththe pinna and the auditory canal are cartilaginous instructure, but are abundantly supplied with vessels, andhence it is that the ears tingle and redden even with veryslight mental emotion. The pinna collects the waves of 182 THE ORGA^^S OF HEAPJXG. [Art. 439. sound and directs them inward to the tympanum, throughthe auditory c
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Keywords: ., bookcentury1800, bookdecade1860, booksubjectphysics, bookyear1867
