Acroslafmi. 283 



Havlno- taken a little wine to recruit my strength, T began 

 some experiments, but they were not satisfactory. I pro- 

 posed to my companion to ascend higher: he consented, 

 ihouoh as much mdisposed as myself. We successivciy 

 tlu-ew out ballast. The mercury in the barometer fell to 

 J2-4 inches. At that height the cold out of the car was 

 insupportai)le, though the thermometer was only one degree 

 below the freezino- point. We were obliged to respire faster, 

 and our pulse beafwith extreme rapidity. We could scarcely 

 resist the strong; inclination to sleep with which we were 

 seized. The blood rushed to our head, and M. Lhoest re- 

 marked that it liiid entered my eyes. My head was so swelled 

 that I could not put on my hat. In this region, where the 

 balloon was invisible from the earth, Mr. Robertson made 

 ihe following experiments : • n ^ 



1st, Having let a drop of ether fall on a piece of glass, 

 it evaporated in four seconds. 



2d, He electrified by friction glass and seahng-wax. These 

 substances save no signs of electricity which could be com- 

 municated to other bodies. The Voltaic pile, which when 

 the balloon was set free from the earth acted with its full 

 force, gave only a tenth part of its electricity. 



3d, The dipping needle seemed to have lost its magnetic 

 virtue, and could not be brought to that direction which it 

 had at the surface of the earth. 



4th, He struck with a hammer oxygenated muriate of 

 potash. The explosion occasioned a sharp noise, which, 

 though not very strong, was insufferable to the ear. It is 

 also °o be observed, that though the aeronauts spoke very 

 loud they could with great difficulty hear each other. 



5th, At that height Mr. Robertson was not able to ex- 

 tract any electricity from the atmospheric electrometer and 

 condenser. 



6th, In consequence of a suggestion from professor 

 Helmbstadt of Berlin, Mr. Robertson carried with him two 

 birds: the rarefaction of the air killed one of them; the 

 other was not able to fly, it lay extended on its back, but 

 fluttered with its wings. 



7 th, Water began to boil by means of a moderate degree 

 of licat maintained with quicklime. 



&th, According to observations made, it appears that the 

 clouds never rise above 2000 toises, and it was on y in 

 ascending and descending through clouds that Mr. Robert- 

 eon was able to obtain positive electricity. 



NATURAL 



