174 Historical 



Paris, December 7, 1785. 

 Gentlemen: 



Probably a mistake slipped into the article which you published 

 on the fifth of this month in regard to the ascent of M. Blanchard, 

 made November 21 near Ghent; it says that he rose to 32,000 feet, 

 which would make 5333 fathoms; the greatest height reached hitherto 

 is 2434 fathoms, and the great expansion of the air would probably 

 make it impossible to rise to or to breathe at a height which is more 

 than double that .... At 2430 fathoms height the barometer is at 

 only 16 inches. M. de la Condamine observed it at 15 inches 11 lines, 

 but no man has seen it lower. If one could rise to 5441 fathoms, the 

 barometer would stand at only 8 inches, and it is probable that hem- 

 orrhage and death would soon be the result. 



De Lalande. 



There follows a table given by de Lalande, indicating the rela- 

 tions between the barometric pressure and the altitude: 



By the way, Lalande reproduces this table in the Yearbook of 

 the Bureau of Longitudes for the year 1805, then he adds: 



The last numbers will probably be eternally useless; human beings 

 will never see the barometer at 11 inches, unless, by artificial means, 

 they succeed in giving air to the lungs and lessening the pressure of 

 the inner air. (P. 94.) 



In the Yearbook of 1806, the remark about the impossibility of 

 reaching 11 inches is suppressed. The only statement is: 



The last numbers are probably useless: M. Gay-Lussac went only 

 to 3584 fathoms. (P. 99.) 



Prudent correction, for 11 inches correspond according to 

 Lalande to 4057 fathoms (7907 meters) , a height far surpassed 

 since then, as we shall see, by Glaisher and Coxwell and by Gaston 

 Tissandier. 



But let us return to Blanchard; he did not consider himself 

 conquered, and replied haughtily in the Journal de Paris: 7 



Gentlemen: 



If I have not replied sooner to the letter written you by M. de 

 Lalande about a so-called error in regard to my ascent at Ghent, in 

 which I say I rose to the height of 32,000 feet, it is not for want of 

 material; I shall not reply even today, intending to discuss his opin- 



