384 Sdentijic Newt, Account of Books, toV. 



Citizen Vidron ufes a rod of ftcel, one end of which he places upon the found-board 

 of the mufical inftrument, and the other between the teeth of the deaf perfon. He adds to 

 it a branch terminated by a brafs button which refts upon the cavity of the ftomach, and 

 fometimes a third which he places upon the head. 



The commiflioners have found that many authors have announced the fa£l of the deaf 

 being made to hear by putting their teeth in communication with the inftrument by means 

 of a ftick, a goblet, or fome other body. They have quoted, amongft others, Fabricius 

 D'Aquapendente, Schelhammer, Boerhaave, Winkla, andjoriffen. 

 " They have alfo found that in like circumftances fteel is better for the purpofe than wood, 

 which had been almoft generally ufed before the tirtie of citizen Vidron; but that his two 

 branches are of no ufe with refpe£l to what may properly be called hearing. 



They particularly endeavoured to determine to what extent this method might be ufeful; 

 as well with refpedl to the difFerent kinds of deafnefs, as to the different kinds of founds 

 which are propofed to be rendered audible. 



They produced an artificial deafnefs in themfelves by flopping their ears, and retiring 

 to a diftance. In both cafes they hearddiftinftly by means of the fteel rod, and the founds 

 appeared to them to proceed from within this rod, and not from their true place. 



But the perfons, really deaf, whom they have examined prefented very different refultj: 

 Some of them manifeftly heard ; but the greater number declared they only experienced a 

 tremulous aftion more or lefs general. 



The commiflioners conclude, that this method may be ferviceablc in deafnefs which 

 only proceeds from obftrudlions in the external paflage, but that it is ufelefs in that which 

 is caufed by a paralyCs of the nerve, or an eflential derangement in the interior part; which 

 is the moft common kind of deafnefs, efpecially in thofe who are deaf from their birth. 

 They think it proper, neverthelefs, to make the experiment on all young perfons who are 

 deaf, fince if only one out of an hundred fhould derive benefit from it, to that one at leaft 

 it would be a fource of enjoyment." 



As to articulated founds or fpeech the commiflioners found that It was almoft impofllble 

 to hope for an exaft tranfmiflion of them by this method, at leaft in its prefent ftate. 



Societe Philomath. No. 41. 



**• 



Mr. Leflie has favoured me with a correflion of his paper, where page 346, line 19, 

 for public opinion the words popular opinion are to be fubftituted. And he fears that 

 other verbal inaccuracies may have occurred, as the copy was written in hafte, and 

 the uncxpe£ted abfence of the author, during the impreflion, prevented any fubfequent 

 revifion. 



