836 Sctetitlfic Niios, (s*r. 



On the Acoujiic Experiments of Chladni and Jacquin. 



M. E. Perrole, fome of whofe experiments on found arc inferted in our Journal, I. 411. 

 has written to Citizen Delametherie * a letter, in which he cxpreffes his doubts refpefting 

 the truth or accuracy of the experiments of Chladni and Jacquin, announced at p. 43 of our 

 prefent volume. His arguments are, in (hort, that Dr. Prieftley, who made experiments with 

 a bell under a jar, fucceflively filled with the feveral gafes, as well as himfelf, did not perceive any 

 fuch difference of tone. He tandidly takes notice, that thefelafl: experiments are different in their 

 circumftances from thofe, in which a flute was ufed ; but does not feem difpofsd to confii. . 

 the difference as of much importance. On this head It may be fufHcient to remark, that the 

 difference, if theoretically confidered, is indeed very great : and that the pradlical refults may 

 moft conveniently be eftabllfhed, or refuted, by the teft of experiment. 



EffeB of Hydrogen Gas on the Voice. 



Odier, in the Bibliotheque Brittanique t, informs us that IVIaunoir, at Geneva, amufing 

 himfelf by refpiring pure hydrogene gas, found it attended with no fenfible efFe£t, either at 

 the infpiration, or when expired; but when after having infpired a confiderable quantity 

 (une forte dofe) he attempted to fpeak, he was flrangely furprized that the found of his voice; 

 had become fhockingly hoarfe and flirill. M. Paul, at whofe houfe this trial was made, 

 repeated it upon himfelf, and experienced the fame efFeft. ' 



* Journal de Phyfique, V. 455. t Quoted by Delametherie, J. de Phyf. V. 459. 



