1824.] Capt. Beaufoy's Aerial Excursion. 211 



emerged from the clouds ; and getting into a new current of air, 

 the balloon turned round again. At three minutes past seven, 

 barometer 26-5 inches, or 3130 feet, every object on the earth 

 became perfectly distinct; and Mr. Graham let down his grap- 

 pling iron, at the end of a cord 160 yards long. 



At seven minutes past seven, barometer 28*3 inches, or 1385 

 feet, thermometer 50°, hygrometer 22° dry, the height of houses 

 and trees became apparent ; and one minute afterwards, the 

 grapple having caught in the boughs of an oak, brought the car 

 to the ground with considerable violence ; and after rebounding 

 two or three times, Mr. Graham and myself stepped out without 

 any difficulty into a field near Godstone. 



In this aerial excursion, I was much surprised to find the 

 atmosphere become drier as we ascended, except only at the 

 height of 2257 feet. After our descent, I had occasion to use 

 my handkerchief, when the sound in my ears was like the report 

 of a pistol. 



The balloon was 63 feet high, by 37^- in diameter, which 

 lemon-shaped figure contains 46,388 solid feet ; and as each 

 cubical foot of common air equals^ 14-oz. the whole weighed 

 3479 lbs. But the inflammable air^used, was 2-1- lighter ^than 

 common air; therefore, ^ lv "*"* 



».&* -,„ 

 f of 3479 = 1392 lbs. weight of gas 



630 lbs. weight of silk, car, aeronauts,. &c. 



2022 lbs. total weight suspended, 



which, deducted from 3479 lbs. gives 1457 lbs. for the power of 

 rising. 



Now the highest point we attained was 11,711 feet, at which 

 elevation the density of the air is "652 ; and by calculation, it 

 appears, we might have reached 14,142 feet without lightening 

 the machine at all ; but if 150 lbs. had been thrown out, to the 

 height of 16,146 feet, or rather more than three miles. 



It does not seem probable that any individual was ever 

 raised in a balloon much beyond this last point. First, because 

 that belonging to Mr. Graham, in which I ascended, is larger 

 than those generally used ; and secondly, the inflammable air 

 becomes so much distended in the rarer atmosphere above, that 

 a great deal escapes out of the safety valve, and more is 

 expended in accomplishing the descent ; so that on approaching 

 the earth, the balloon collapses, and falls with an alarming- 

 rapidity. 



It is true that many balloons are supposed to have reached a 

 far greater elevation ; and one French gentleman was particu- 

 larly fortunate in that respect. But, perhaps, the gas he used 



p2 



