340 AERONAUTIC VOYAGES. 



the thermometer +7°; at the same instant the barometer of the Observatory- 

 indicated a pressure of 753.17 millimeters, and the thermometer + 19°.4. These 

 numbers give, by calculation, the height of 4',242 metres above the mean level 

 of the sea, and correspond with the moment at which the balloon emerged from 

 the upper part of the clouds. The bed of clouds now below the observers pre- 

 sented the appearance of mamillary swellings, silver white in color, the light 

 from which, examined with the polariscopic telescope, yielded no trace of polari- 

 zation. Except a few clouds, which here and there rose high above the balloon, 

 the sky was of a pale and .dull blue. At 10 hours 59 minutes the barometer of 

 the car indicated 373.4 millimeters, and the thermometer had sunk below zero. 

 M. Barral was unable to make out the exact thermometric degree on account of 

 a layer of hoar-frost deposited on the instrument, which he could not remove. 

 The barometer was at this time in a state of oscillation, the mean height of its 

 changes being represented by the number just mentioned. The balloon, which, 

 notwithstanding the precise directions given, had been so constructed as not 

 to leave sufficient room for the development incident to the natural dilatation 

 of the hydrogen,* had now sunk down upon the excursionists ; the valve pro- 

 vided for the escape of the gas was closed ; a rent had taken place in the upper 

 part of the balloon, and MM, Barral and Bixio fell to the earth after having 

 traversed 5,800 meters in from four to five minutes. 



They immediately commenced preparations for a new ascent, which took 

 place a month after that of which an account has been given. They rose, as 

 before, from the garden of the Observatory ; and I was a witness of this, as I 

 had been of their former ascension. I had taken part in all the deliberations 

 which regarded the scientific purposes of the voyage. If the first one had been 

 rendered, by imfavorable circumstances, almost entirely barren of results, beyond 

 giving proof of the intrepidity of the two distinguished explorers, and initiating 

 them in the dangers of an ascent through an atmosphere agitated by winds and 

 turbid with thick clouds, it would be sufficient to read the journal of the second 

 voyage to comprehend how fertile it was both in novelty and interest. The 

 Academy of Sciences having judged it desirable that such a statement should 

 be prepared as would enable those least familiar with these matters to appre- 

 ciate the importance of the contribution made by MM. Barral and Bixio to 

 meteorology, I yielded to the wishes of that learned body, and shall here 

 reproduce, in nearly identical terms, the account of the voyage which I then 

 submitted : 



" The two scientific explorers having properly resolved to renew their enter- 

 prise under more favorable circumstances, and being no longer under a neces- 

 sity of evincing their courage or punctuality, could afford to await patiently 

 the day arid the moment. M. Regnault took charge, with JM. Barral, of the 

 preparations, which is equivalent to saying that the utmost ingenuity and 

 exactness presided over the construction and disposal of the instruments. No 

 one, hoAvever, but an eye-witness, can appreciate the indefatigable zeal and 

 devotedness Avhich my distinguished colleague exerted day and night in this 

 behalf. 



" Everything was ready on Friday, July 26, 1850, but the weather was 

 adverse. Saturday morning, the atmosphere having cleared up, the filling of 

 the balloon was begun. The operation was tedious, and by the time it was 

 finished, towards one or two o'clock, the sky was overclouded, and a deluge 

 of rain Avas falling. The rain finally ceased, but the sky remained entirely 

 overcast; it would have been only natural, under these circumstances, to 



*■ The difficulty of mana!^m<T tho balloon before its ascent Avas the reason why the length 

 of the cords attachinfi^ tlio car aves reduced. The Avind was so violent that 120 soldiers could 

 scarcely keep tho balloon from being carried away. 



