442 PHILOSOPHY OF STORMS. 



a sufficient quantity of vapor would be condensed to produce 

 such rains as occur in nature ; that is, in the Catskill shower, 

 for instance, more than twice as much vapor as the whole 

 atmosphere over the region of the rain contained. Although, 

 if the advocates of this theory were to calculate the quan- 

 tity, they would find that not half an inch of rain would be 

 produced, if the two halves of the atmosphere were mingled 

 together, both saturated with vapor, one at the temperature 

 of 80, and the other at zero. It supposes, in the case of 

 hail, that the hailstone commences its formation at a great 

 height, with a small nucleus, and receives continual acces- 

 sions of matter in descending, until it reaches the ground; 

 at which time, in some well authenticated instances, it is a 

 foot in circumference ; and this is the Professor's own theory. 

 [Silliman's Journal, vol. 18, page 11.] 



Now this is not only an hypothesis, but contrary to the 

 known laws of nature. For, to say nothing of the heat of 

 the lower air, which would have a tendency to melt the 

 stone in part as it descended, it is known that it would be 

 all melted by the caloric of elasticity alone before it would 

 condense upon itself one-seventh of its whole weight of 

 vapor. This may easily be conceived and demonstrated, 

 by holding a piece of ice in the steam which issues from an 

 opening in a steam boiler; for it is known that steam con- 

 tains the same quantity of caloric, at all temperatures. 

 And even if the nucleus had been 57 below zero the- 

 temperature of the interplanetary spaces ' it would not 

 condense on itself one tenth of its own weight before it 

 would be raised to the temperature of 32, at which point a 

 further accession of vapor would diminish its size. It sup- 

 poses that the air in the region where clouds are formed, 

 contains a sufficient quantity of vapor to form such clouds 

 and rain as nature produces ; whereas a knowledge of the 

 dew point would teach its advocates that all the vapor 

 which the air contains, above the region of perpetual con- 



1 According to Fourier Pouillet, however, makes it much more. 



