CHAP. V.] 



AERIAL NAVIGATION. 



103 



MM. Barral and Bixio in 1850, and the thirty ascents which Mr. 

 Glaisher made from 1860 to 1865. Among the most curious results of 

 the second ascent of the two first savants, we will quote the following : 

 they discovered the existence, in the height of summer, of clouds 

 entirely formed of icicles, of a thickness of 4 kilometres (13,480 feet) ; 

 reaching the height of 7 kil "49 (24,600 feet), where MM. Barral and 



FIG. 63. Mr. (Jlaisher's car ready for n scientific expedition. 



Bixio found a temperature of 39 Fahr. below r zero, nearly that of 

 the freezing point of mercury. 



Mr. Glaisher's journeys, together with those of the young and 

 courageous French aeronauts, MM. de Fonvielle, Flammarion, and 

 Tissandier, made one or two years ago, are described in detail in 

 an interesting work, Travels in the Air, edited by Mr. Glaisher 

 himself, to which we refer the reader who is curious to be initiated 

 into the conditions of this kind of locomotion. 



