1814.1 Journal of an Aerial Voyage. 289 



able, and this at an elevation of nearly 3C00 feet. All sounds 

 seemed to be transmitted with distinctness to us aloft, at a distance 

 in which we could not make ourselves heard by those under us. 

 This was to be expected, as there could be no objects near enough 

 to the balloon to assist in reflecting the sound ; whereas to those 

 beneath us this objection did not apply; the hills and hollows all 

 tending to influence the propagation of sound on the earth. It did 

 not appear that any change in the state of the atmosphere affected 

 the propagation of sound. This was contrary to my expectations. 

 For some years since, when Colonel Beaufoy was out on a shooting 

 party on one of the Swiss mountains, in company with the late Sir 

 Harry Mildmay, they were enveloped in a very dense cloud ; by 

 accident Sir Harry's fowling-piece went off, and the report was in- 

 stantly followed by a complete roll, like that of thunder. The ex- 

 periment was repeated again and again with similar results. Co- 

 lonel Beaufoy waited there some time, till the cloud had cleared 

 away, and the ordinary clearness of the atmosphere was restored. 

 He again tried the effects of the discharge of his piece ; but now, 

 m roll followed. 



' , made at the different Periods of the above Observations. 



Oi 'i l made at Hackney Wick, at the moment the 



balloon was teen rising over the' trees, and a< the data from 



which tl us were to be made during the voyage. The 



were occupied in fixing the instruments, and regu- 



of the barometer. Mr. Sadler directed me to ax- 



ihserotiont, and that he would himself look to 



■ ol the balloon. Assisted in putting to lights and 



coiling away rope, grapnel, &c, &c. which were lying in a confused 



