1825.] 



Vdocity of Sound, 



279 



the number of observations, gives the passage of sound along 

 the basis 52'',37. Thus the mean velocity in V was 337'",39 

 = 1107,268 feet. 

 The mean temperature at the time of these experiments 



Centigra4e. 



at Zevenboompjes 7% 41 



Kooltjesberg 8 , 54 



Mean temperature of the air ... 7 ,975 = t 



Mean height of the barometer corrected for capillarity, and 

 at 0"^ cent, 



at Zevenboompjes .......... 0'",7522 



Kooltjesberg ,7538 



Mean barometer ,7530 = p 



Mean tension of aqueous vapour in the air, 



at Zevenboompjes 0,00737444 



at Kooltjesberg 0,00706966 



Mean tension 0,00722205 = F, 



which quantities substituted in the formula, we have for tem- 

 perature 0° cent, and in perfectly dry air the velocity of sound 

 U' = 331,85 metres = 1089,087 feet. 



Experiments of 26th June, 1823, when the Shots were not reci- 

 procal. . V • : ' ' 



The 26th of June, the following shots werejeeit ind heard at 

 Kooltjesberg and fired at Zevenboompjes, but no shots from 

 the first station were heard at the lattec. .*.;;^a, v*"w.^ i.i.^.o 



