CHAPTEE IX. 



CLOUD FOKMATION CONTINUED. 



As water in its condensed state is 815 times 

 heavier than air, the question naturally comes 

 to one why it does not immediately fall to the 

 earth when it condenses. There are at least two 

 and probably more stages of condensation. In- 

 vestigators into the phenomenon of cloud for- 

 mation claim to have ascertained that the first 

 effect of condensation is to form little globes 

 of moisture that are hollow, like a bubble, with 

 very thin walls. Everyone has recognized the 

 ease with which a soap bubble will float in the 

 air, and yet it is simply a film of moisture. 

 These little balloons, so to speak, are called 

 spherules. It is undoubtedly the case that 

 mingled with these little bubbles of moisture 

 there are fine particles of solid water hanging 

 on and carried along with them. Undoubt- 

 edly this is true; at least just before the final 

 act of condensation takes place ; and when the 

 little hollow spherules collapse they are gath- 

 ered together in drops of water larger or 

 smaller according to the rapidity of condensa- 



69 



