«2 Experiments on Sound. 



tion of the glottis, the bird produces tones fo much higher 

 as the trachea is fhorter, and all the harmonics befides which 

 correfpond to that degree of contraction. 



Obfervations which confirm the utility of the muriate of 

 mercurius dulcis in the cure of the fmall pox, by Cit. De- 

 feflarts, as well as the profound refearches of Cit. Huzard on 

 a malady which affe&s the organs of generation in horfes, 

 engaged likewife the attention of the clafs. 



Several of its members have made it their particular care 

 to confirm, by repeated experiments, the phenomena of 

 Galvanifm. (See Report of the Commiffion appointed to 

 examine this phenomenon, p. 319.) 



PRODUCTION OF SOUNDS EY DIFFERENT GASES. 



J. F. Jacquin, profefTor of chemiftry at Vienna, in a 

 letter to M.-Dclametherie, gives the following account of 

 fome curious experiments which he made lately on this fub- 

 jecl : " ProfefTor Chladni at Wittemberg, already cele- 

 brated by feveral difcoveries in the theory of the phenomena 

 of found, induced me, during his refidence at Vienna, to 

 make experiments on the property of different gafes con- 

 fidered as fonorous bodies ; and particularly on that gas 

 which conftitutes our atmofphere, and ferves as the organ of 

 voice. We took a glafs bell furnifhed at the top with a 

 brafs cock, fuch as that ufed for filling bladders with gas, 

 and made the internal aperture of the cock to communicate 

 with a fmall tin flute, about fix inches in length. This bell 

 being placed in the pneumatic tub, and filled with gas of any 

 kind, a bladder with a cock, and filled with the fame gas as 

 the bell, was fitted to the cock of t'.ie bell, and by preffing 

 the blad 'er gently the flute was made to found. Compara- 

 tive experiments were repeated in this manner with atmo- 

 spheric air, oxygen gas, hydrogen, the carbonic acid, and 

 nitrous gas. The ftrengtl* of the found was always the fame: 

 but, compared with that in atmofpheric air, the oxygen gas 

 gave half a tone lower \ azotic gas, prepared different ways, 



gave 



