CATAtOGiJE.— ACUSTies, SOURCES OF SOUND. 



267 



The sound of carbonic acid gas, nitrous gas, and oxygen 

 gas, agreed with the theory ; but azote, of which the spe- 

 cific gra»ity was .Q85, common air being unity, gave a note 

 half a tone lower than common air. Hydrogen gas pro- 

 duced a note an octave or a minor tenth higher. 



Delarive on the sounds from hydrogen o-as. 



Journ. Phys. LV. l65. Nich. 8. IV. 23. Ph. 



M. XIV. 24. 

 Higgins on the sound from hydroj^en gas. 



Nich. 8. I. 129. 

 A harmonica. Gilb. XVIJ. 482. 



A glass tube sounding while hot. 



The air in a flute is like a slow river with waves moving 

 npidly along it. 



Account o/M. Delarive's Memoir on the Sounds produced 

 by Imrning Hydrogen Gas. Journ. R. I., I. sag. 



It is well known, that when a stream of hydrogen gas 

 passes through a small tube, and is inflamed at its orifice, 

 if a large tube be held over the flame so as partially to in- 

 close it, an agreeable sound is frequently produced. The 

 frequent failure of the experiment, and the impossibility of 

 producing the same effect with other kinds of flame, left 

 considerable obscurity with respect to the immediate cause 

 of the sound. M. Delarive appears to have been very 

 successful in his attempts to remove these difficulties. He 

 supposes the continual production and condensation of 

 aqueous vapour to cause a brisk vibratory motion, which 

 must be able, in order to produce a sound, to harmonize 

 with the dimensions of the tube, and is then regulated and 

 equalised by the regular reflections from the tube, so as to 

 constitute together a clear musical sound : he observes that 

 for this purpose there must be a great difference of tempe- 

 rature in the air and the tube near the flame ; hence the 

 failure of the vapour of ether, which produces too slight a 

 degree of heat, and the difficulty of succeeding in a warm 

 room, for want of a sufficient supply of cool air. This ex- 

 planation is confirmed by a curious experiment on tubes 

 with bulbs resembling that of a thermometer, in which a 

 small particle of water or mercury is exposed to a conside- 

 rable heat, so as to be wholly converted into vapour, while 

 the upper part of the tube remains cool ; in this case a sound 

 is produced somewhat similar to that of hydrogen gas, but 

 much fainter. Brugnatdli has obtained a sound from 

 Idiosphorus burnt in a tube ; and M. Delarive supposes 

 that the phosphorous acid, in the form of a vapour, pos- 

 sesses a high degree of elasticity, and that it is condensed 

 with sufficient rapidity for the production of the sonorous 

 effects. Y. 



Vibrations of Solids. 



Chords. 



Lahire on the trumpet Marigni, A. P, IX. 

 530. 



Taylor de motu nervi tensi. Ph. tr. 1713 

 XXVIII. 26. 



Sauveur on the sounds of chords. A P. 1713. 

 324. H. 68. 



Jo. Bernoulli on vibratins: chords. C Petr 



III. 13. 

 D. Bernoulli on the curvature of an extended 



chord. C. Petr. III. 62. 

 D. Bernoulli on vibrating chords. A. Bierl. 



1753. 147, 173. 

 Bernoulli on the vibrations of unequal chords. 



A. Berl. 1765. 28 J. 



Some may be harmonious though unequal ; others in- 

 harmonious. 



Bernoulli on the vibrations of compound 



chords. N. C. Petr. XVI. 257. 

 Euler on the vibrations of flexible and rigid 



bodies. C. Petr. VII. pg. 

 Euler on the oscillations of flexible bodies. 



C. Petr. XIII. 124. XIV. 182. 

 On the motion of flexible bodies. A. Berl 



1745.11.54. 

 Euler on the vibration of chords. A. Berl 



1748.69. 

 Euler's remarks on Bernoulli. A. Berl 1753 



196. 

 Euler on the vibrations of a loaded thread 



N. C. Petr. IX. 215. 

 Euler on the vibrations of unequal chords 

 N. C. Petr. IX. 246. 



Euler on the propagation of agitations. M. 

 Taur. II. ii. 1 . 



Euler on the agitations of chords. A. Berl. 



1765.307,^335. 

 Euler on equal and unequal chords. M. Taur. 



III. ii. 1, 27. 



