THE PHONOGRAPH 303 



is due to the entrance and exit of air in the tube. Several 

 small bones stretch across the upper portion of the cavity 

 and make a bridge, so to speak, from the ear drum to the far 

 wall of the cavity. It is by means of these three bones that 

 the vibrations of the ear drum are transmitted to the inner 

 wall of the cavity. Behind the first cavity is a second cavity 

 so complex and irregular that it is called the labyrinth of the 

 ear. This labyrinth is filled with a fluid in which are spread 

 out the delicate sensitive fibers of the auditory nerves; and it 

 is to these that the vibrations must be transmitted. 



Suppose a note of 800 vibrations per second is sung. Then 

 800 pulses of air will reach the ear each second, and the ear 

 drum, being flexible, will respond and will vibrate at the same 

 rate. The vibration of the ear drum will be transmitted by 

 the three bones and the fluid to the fibers of the auditory 

 nerves. The tremors imparted to the auditory nerve reach 

 the brain and in some unknown way are translated into sound. 



278. Care of the Ear. Most catarrhal troubles are accom- 

 panied by an oversupply of mucus which frequently clogs up the 

 Eustachian tube and produces deafness. For the same reason, 

 colds and sore throat sometimes induce temporary deafness. 



The wax of the ear is essential for flexibility of the ear drum ; 

 if an extra amount accumulates, it can be got rid of by bathing 

 the ear in hot water, since the heat will melt the wax. The 

 wax should never be picked out with pin-or sharp object except 

 by a physician, lest injury be done to the tympanic membrane. 



279. The Phonograph. The invention of the phonograph 

 by Edison in 1878 marked a new era in the popularity and 

 dissemination of music. Up to that time, household music 

 was limited to those who were rich enough to possess a real 

 musical instrument, and who in addition had the understand 

 ing and the skill to use the instrument. The invention of the 

 phonograph has brought music to thousands of homes pos- 



