CATALOGUE. ACUSTICS, EFFECTS OF SOUXD. 



&69 



Riccati on elastic force. C. Bon. I. 523. 

 •Kiccati on ihe sounds of cylinders. Soc. 

 Ital. I. 444. 



With many experiments, and tables for forming the 

 scale. Corrects some material errors of Euler. 



Lexell on the vibrations of rings. A. Petr. 



1781. V.ii. 18.3. 

 Lambert on the sounds of elastic bodies. N. 



Act. Helv. I. 42. 



With experiments. Makes the series 1, 0.267,17.54?, 

 34.38. An approximation only. 



*Chladni Entdeckungen liber die theorie des 



klangcs. 



Finds the vibrations generally agreeing with theory ; 

 that is, nearly as the squares of the odd numbers in most 

 cases ; in one, as the squares of the natural numbers. The 

 sounds of rings do not agree with either of Euler's supposi- 

 tions, but are nearly as the squares of the odd numbers. 



Acccount of Cliiadni's figures. Journ. Pliys. 



XLVII. (IV.) 390. Ph. M. II. ,'315, 3yi. 

 Jo. Bernoulli on the vibrations of rectangular 



plates. N. A. Petr. 1787. V. 19.7. 



Compared with Chladni's experiments. 

 PerroUe. M. Tiir. 1790. 1. App. 209. 

 Voigt on Chladni's figures. Ph. M. HI. 389. 

 Parseval on the complete integration of the 



formulae for the vibrations of plates. To 



be printed in the Mem., des sav.etr. of the 



Institute. 

 See page 84. 



Longitudinal Vibrations. 



ChlaSni liber die longitudinal schwebungen 



der stabe. 4. 



From the transactions of the society at Erfurt. 

 On Chladni's longitudinal sound. Ph. M. 



IV. 



Spiral Vibrations. 



Chladni on spiral vibrations. Gilb. II. 87. 

 Ph. M. XII. 259. 



From the memoirs of the Naturf. Fr. These vibrations 

 »re found to be a fifth lower than the longitudinal vibrations. 



Effects of Sound. 



Remarks on the Effect of Sound upon the Ba> omeler. By 

 Sir Henby C. Englefield, Bart. F. R.S. Journ. R. I., 

 I. 157. 



During the time I spent at Brussels in the years 1773 

 and 1774, it occurred to me, that the effect of sound on 

 the barometer had not, to my knowledge, been attended 

 to ; and that it was by no means certain, whether that in- 

 strument was capable of being sensibly affected by those 

 elastic vibrations caused in the atmosphere, by the percus- 

 sion of a sonorous body. I thought the idea worthy of be- 

 ing pursued, and the means of making satisfactory experi- 

 ments were most opportunely in my power. 



The sound of a very large bell appeared to me the most 

 powerful, and, at the same time, to be approached with the 

 greatest security and ease to the observer. The explosion 

 of artillery, besides the very disagreeable smoke and danger 

 ofthe recoil, might be objected to, on account of the sud- 

 den production of elastic and heated vapour, which might,, 

 independent of the sound, instantaneously alter the state of 

 the atmosphere, and thereby lead the observer into very 

 great and unavoidable errors. 



Every one who has been in the Low Countries must 

 know, that very large bells, and immense numbers of them, 

 are the pride of theh: churches, and that they are rung quite 

 out, not tolled, on every great festival. The great bell of 

 the collegiate church of St. Gudula, at Bru.ssels, weighs, as 

 I was told, sixteen thousand pounds, and on this I deter- 

 mined to found my experiment. 



Two objections only could be made to the result of this 

 trial, the one, that the motion of the bell might cause a vi- 

 bration in the \\'alls of the building, v.hich would hinder 

 the placing the barometer in a state of repose ; the other, 

 that the swinging so large a mass with a considerable de- 

 gree of velocity, might of itself agitate the air so as to cause 

 vibrations in the mercury, totally independent of sound. 



The strength of the walls of the steeple, and manner of 

 hanging the bell, which was contained in a frame of timber, 

 founded on a strong vault, and totally independent of the 

 walls of the steeple, might alone have answered the first of. 

 these objections, but happily a most complete and satisfac- 

 tory answer to both of them was furnished by the manner 

 in which the bell was rung. 



As the bell was to ting out full in an instant, at a signal 

 given from below ; it is necessary to have it in motion some 

 time beforehand ; and during that time, the clapper is fixed 

 to one side by a strong stick crossmg the mouth of the bell, 

 which, at the signal, is pulled out by the hand of a person 

 placed for that purpose. If, then, our barometer showed: 



