206 If/*. Goldingham on the Velocity of Somid, [Sept, 



Feet. 



We then have by the Mount gun 1142-18 for the velocity. 

 And by the Fort gun 1142-5. 



The mean is 1142-34, or very nearly the velocity above 

 alluded to. Nothing could be more satisfactory than this gene- 

 ral result ;* and it may be presumed, that the other results in 

 different states of the atmosphere are equally to be depended 

 upon. 



The velocity also by the Fort gun, which, it will be recollected, 

 is little more than half the distance of the Mount gun from the 

 station, shows that sound travels equally during its progress. 



In the NE monsoon, the sound was very indistinct at times : 

 this however does not appear to have sensibly affected its motion. 

 The French academicians indeed proved, that this made no 

 difference in the velocity. 



I shall now proceed to the conclusions from the other Tables ; 

 and first, those of the experiments with the Mount gun. 



The results in these Tables, hke the separate observations, 

 show the necessity of making a series of experiments long conti- 

 nued, in order to obtain the correct general rate at which sound 

 travels ; and this may afford a clue, as I observed in the first 

 part of this paper, for discovering the cause of the differences in 

 the results by the authorities there named : it is difficult, 

 undoubtedly, to ascertain the distance of two stations, one far 

 from the other, to the nearest foot ; but errors of many feet in 

 this respect, would make but a small difference in the velocity in 

 a second found by experiment, when the gun and station were 

 even at a moderate distance jf we must, therefore, be led to 

 conclude, that these differences have chiefly arisen frpm the 



• The results by the Mount gun may however be taken as the standard. 



■f For example, a difference of about '4! 6 feet in the distance, between tlie Observatory 

 station and the Blount gun, would make only about a foot difference in the velocity in a 

 second. 



