SKETCH OF PROFESSOR MAYER. 233 



the ossicles of the ear, and proposed on these facts a new hypothesis 

 of the mode of audition. 



9. He first discovered the law connecting the pitch of a sound 

 with the time that the sensation of the sound endures after the air 

 has ceased to vibrate the tympanic membrane. This law rendered 

 the qualitative results of Ilelmholtz quantitative ; and in the third 

 edition of Helmholtz's " Tonempfindungen " Mr. Alexander J. Ellis, 

 as noted above, has extensively used this law as the only basis for 

 reaching exact quantitative results in the fundamental phenomena 

 of musical harmony. This law Prof. Mayer has applied extensively 

 to the elucidation of the fundamental facts of harmony, and to 

 the explanation of many obscure phenomena in the physiology of 

 hearing. 



10. He discovered that sonorous sensations interfere with one 

 another, and that, although a low sound may entirely obliterate the 

 sensation of a sound higher in pitch, yet a sound cannot in the slight- 

 est obliterate the sensation of another sound lower than it in pitch. 

 He has made applications of these discoveries in showing that a radi- 

 cal change is required in the usual method of conducting orchestral 

 music, and in a new method of determining the relative intensities of 

 sounds. 



11. He has determined with great precision the laws of the vibra- 

 tions of tuning-forks, especially in the direction of the bearing of these 

 laws on the action of chronoscopes used in determining the velocities 

 of projectiles. He first accurately gave the correction to be applied 

 in all such determination on account of the different temperatures of 

 the forks. 



Besides these difficult and delicate original investigations, Prof. 

 Mayer has contributed numerous articles to Appletons' and Johnson's 

 " Cyclopaedias " in his more especial lines of inquiry, and has written 

 much for various popular publications. He was one of the editors 

 of the American Journal of Science and Arts, but reluctantly gave 

 up its duties in 1873 on account of weakness of sight. He then 

 suspended work, and went to England for a vacation, where he was 

 cordially received and kindly entertained by his brethren of the 

 various scientific societies. 



