The experiment of making the deaf to hear and the mute to speak was tried yesterday in the Pennsylvania Institution for the Deaf and Dumb by Mr. R. S. Rhodes, of Chicago, who, having long experienced the privation of infirm auditory organs, invented a carbon disc, the testing of which as a conductor of sound was the object of yesterday's trial. Those who came to see how the new invention would work were welcomed by the superintendent, and accommodated with chairs in the ample parlors of the institution.

Among those present were E. Mortimer Lewis, David P. Brown and George P. Kimball. Not a few of the interested auditors were enabled to follow the proceedings by means of Audiphones, and all such cheerfully added their testimony to the great amelioration of what was in some cases almost total deafness of many years' standing. The apparatus for the experiments consisted of a grand piano and several Audiphones.

Mr. Rhodes, the inventor, remarked introductorily that only those whose auditory nerve was not wholly dead could be benefited. Very few, however, even of those born deaf, are totally without sense of sound, hence nearly all of those educated in the asylums may be taught to speak, inasmuch as their dumbness is owing solely to their want of use of the organs of speech.

A Deaf Girl Hears.

Miss Ida Brook was first experimented with. The superintendent said she could hear very loud sounds in favorable weather without mechanical assistance. Mr. Rhodes, standing where his lips could not be seen, spoke at the top of his voice twice, but Miss Brook did not betray the faintest sign of having heard. An Audiphone was adjusted for her, and similar sounds were heard by her, as her pleased ex-pression showed. She also heard single notes sounded on the piano up to ten feet distance, beyond which she seemed not to hear. Practiced on A and O she heard well enough to repeat them with reasonable accuracy, much of her facility having doubtless resulted from her cleverness of interpreting the movement of the lips. Mr. Rhodes covered his own face with an Audiphone, and Miss Brook was still able to repeat the sounds, and make the appropriate mute letter signs at the same time.

To illustrate the necessity of long practice to enable even those who hear to speak, Ellen McClurg was next called up. She is about 10 years old, and born of deaf mute parents. She never until lately heard any spoken words. She understood English no better than if she had been Chinese. Words she repeated accurately, but without any sign of understanding their significance. She was intelligent enough in the mute signs.

Mayor Medill's Bet.

The great editor of the West—Medill, of The Chicago Tribune—was deaf. He made two promises, viz.: One to his wife, that he would attend church; the other that he would pay a thousand dollars to any ingenious individual that would let him drop his speaking trumpet. Since then Edison and all the inventors have been "going for Medill." It was at the convention of the Western Associated Press, held a few weeks ago, that Medill lost. Rhodes, who struck page 29 the idea, told him that he hadn't yet got all the patents. So Medill (who looks all the world like Ex-House of Correction Manager Thomas A. Barlow, with a speaking trumpet at his ear) went to the last convention keeping "mum;" and while the youngsters of the newspaper business, like Henry Watterson, James B. McCullagh, of the Globe-Demotrrat, and Murat Halstead and Wash. B. McLean, were trying to arrange their situation of affairs, Medill was quietly holding a fan-like arrangement in his mouth, between his teeth, and when he got tired of holding it that way gave it to the fellows around him to fan themselves with. In the meantime Medill heard everything, and it is reported did great execution in freeing the newspaper press by the first of the year from telegraph monopoly—just by this Japanese fan. And the worst of it is, it is said Medill has to fulfill the second consideration that he promised his wife—that is, to go to church.