NATUEAL PHILOSOPHY. 



141 



that penetrates, with the countenance of a student and philosopher, 

 and is at the disadvantage of having to be fully conscious and self- 

 possessed, instead of having the aid of the swing and the impetus of 

 passion. The cool feats of our scientific men are known to us all 

 such as that of Sir Humphrey Davy inhaling a particular gas with an 

 accurate report every minute or two of its successive effects upon his 

 brain and senses ; but the aerial voyage of Messrs. Glaisher and Cox- 

 well deserves to rank with the greatest feats of our experimentalizers, 

 discoverers, and travellers. It is true that these gentlemen have not 

 brought down a very comfortable or inspiring report of the upper 

 world into which they have penetrated ; but they" have, nevertheless, 

 furnished one more striking and impressive scene to the history of 

 science. They have shown what enthusiasm science can inspire, and 

 what courage it can give. If the man, as the poet says, had need of 

 ' triple steel about his breast ' who first launched a boat into the sea, 

 certainly those had no less need of it who first floated in the air six 

 miles above the surface of the earth." 



From a mean of all his observations, Mr. Glaisher presented to the 

 British Association the following table, showing the mean temperature 

 of the air at every five thousand feet of elevation above the level of 

 the sea in each high ascent : 



The results on July 17 are perfectly anomalous. Up to 10,000 feet 

 the decrease accords with the other days of experiments ; but from 

 10,000 feet the results are perfectly surprising, and continue so up to 

 more than 20,00-0 feet. Above 25,000 feet they are again accordant. 

 If we suppose that up to 10,000 feet and again at 25,000 feet the 

 results are not abnormal, by continuing the curve joining these two 

 portions, and then reading, we should have the following readings, 

 namely: at feet the mean temperature was 61.2; at 5,000 feet, 

 39. 7 j at 10,000 feet, 27.5; at 15,000 feet, 22.7; at l'J,500 feet, 



