CONSTRUCTION OF BALLOONS. 8? 



danger. They also expedite the communication of important events 

 by signals, and serve for exploring from a great elevation adjacent 

 coasts or regions, fleets and armies. Thus, the French ascribe to 

 the elevation of a balloon, and the information obtained in conse- 

 quence of thus recounoitering the army of the enemy, the signal 

 \iotory gained in the battle of Fleurus, in 17Q4. Balloons may like. 

 wise serve to explore and ascertain the nature of the air in the higher 

 regions of the atmosphere. One of the finest experiments made on 

 this point is that of Gay-Lussac ; who, being elevated in a balloon to 

 the height of 6900metres(nearly eight miles) the greatest ever attained 

 by any person, brought some atmospheric air from those regions, 

 which on being analysed, was found to furnish the principles of 

 oxygen, azote, Indrogeu, and carbonic acid gas, in the same proper. 

 tions as at the surface of the earth. Balloons would also enable us 

 to determine the changes in the direction of the winds at different 

 altitudes, and the law of the diminution of heat at different eleva. 

 tions. In fact, the application of these machines to the advance- 

 ment of our knowledge of the various phenomena in meteorology 

 stands prominent, as the, perhaps, only means of maturing our 

 acquaintance with causes )tt known only by their effects. Their use 

 will also be indicated in many urgent cases where other means of 

 conveyance might fall short. At the same time we conclude with 

 remarking, that the hitherto unsuccessful attempts to render aerial 

 navigation of service to mankind, ought to furnish no argument for 

 causing it to be discouraged by men of sense, or prohibited by civil 

 authority. Many arts and sciences from which commercial nations 

 now derive so much benefit were long in rearing to maturity, and 

 were only at length produced for the public good, in consequence of 

 patient investigation and reiterated experiments. Much useful in. 

 formation on the theory and practice of aerostation may be obtained 

 from Baldwin's Aeropaidia, Cavallo on Aerostation, and Description 

 des Experiences Aerostatiques, par M. Faujas St. Fond. 



[Pantologia. 



a 4 



