THE 

 LONDON AND EDINBURGH 



PHILOSOPHICAL MAGAZINE 



AND 



JOURNAL OF SCIENCE. 



[THIRD SERIES.] 



JULY 1839. 



I. Note on the Velocity of Sound. By Professor Miller, 



St. John's Coll., Cambridge, June 13, 1839. 

 TN the discussion of Moll's experiments on the velocity of 

 *- sound, by Dr. Simons (Phil. Trans. 1830, page 21 1) there 

 are two small arithmetical errors. The observations (9.) and 

 (26. )> made on the 27th of June 1823, give respectively 

 51-895 sec. and 51-985 sec. instead of 51-84-5 and 51*335 as 

 stated by Dr. Simons. The correct mean value of the time 

 in which sound travelled 17669-28 metres is 51-9873 seconds. 

 The mean temperature during these observations was 11°-01 

 C. The mean pressures of the atmosphere and of the vapour 

 contained in it were equal to the pressnres of 0-74618 and 

 0*00889 metres of mercury at 0° C. respectively. It appears 

 from the recent experiments of Rudberg (Poggendorff's 

 Annalen, xli. 558; xliv. 119) that the volume of dry air at 

 100° C. divided by its volume at 0'^ C under a constant press- 

 ure, is equal to 1-365. Hence, at the temperature T'^ cen- 

 tigrade, the pressure of the atmosphere and of the vapour 

 contained in it being IT and T respectively, the velocity of 

 sound in English feet per second will be 



1+0-00365 T' 

 1090-77 



, r 1+0-00365 

 \/|l -0-375^ 



» Communicated by the Author. 

 P/iil. Mag. S. 3. Vol. 15. No. 93. July 1839. B 



