432 PHILOSOPHY OF STORMS. 



wise that it did not radiate all its caloric of elasticity as 

 fast as it was evolved, or it would not have so much left, 

 to radiate for hours after the cloud was formed. 



Besides, there was no answer attempted to be given to 

 the observations of Sausseur, that when he was enveloped 

 in a cloud rising up to him on the side of a mountain, his 

 thermometer rose higher than it was in the open sun. 



Nor was there any mention made of Mr. Durant's and 

 Gay-Lussac's observation, of a similar nature, as they 

 passed through a cloud in a balloon. But what shall I say 

 of the Professor's altogether neglecting to mention the 

 proof which I brought forward, by an experiment with the 

 nephelescope, that the air is not only warmer when a cloud 

 is formed by the cold of expansion from diminished pressure, 

 than it would be with the same expansion when no cloud 

 is formed, but also showing the exact number of degrees it is 

 warmer. This experiment lies at the very foundation of the 

 theory, and, as it was not denied, it was tacitly admitted. 

 If so, the foundations of the theory have not been shaken. 



There is one part of the professor's strictures I would 

 willingly pass by unnoticed, if justice to my subject did 

 not demand a reply. The Professor said that my ex- 

 periments proved nothing as to the formation of clouds in 

 nature, for in my experiments, the air was first condensed 

 and then rarefied, and though a cloud is formed in the ne- 

 phelescope, yet it would not be formed so. by nature, for she 

 never condenses first. Now, one of two things is certain 

 from this declaration ; either the Professor was ignorant of 

 the common experiment with the air pump, in which a 

 dense cloud is formed in a receiver by suddenly exhaust- 

 ing a portion the air from it, and that, too, without any 

 previous condensation ; or he wilfully avoided the main 

 question, knowing the statement which he made was a 

 mere evasion. It is not for me to say which was the 

 fact. 



