CHAPTER XLII 



THE VELOCITY OF SOUND 



UNDER that big white cloud that you call 

 cumulus, " said Emile, " there is at this 

 very moment a storm. We have just seen the light- 

 ning and heard the thunder. Here, on the contrary, 

 the sky is blue. So it does not rain everywhere at 

 the same time. When rain is falling in one country, 

 it is fine in others. And yet, when it rains here the 

 whole sky is covered with clouds. " 



"You need only put your hand over your eyes 

 to hide the sky," his uncle explained. "A cloud 

 much farther off, but also much larger, produces the 

 same effect: it veils what is surrounding us and 

 makes it all cloudy. But that is only in appearance ; 

 beyond the region covered by the cloud the sky may 

 be serene and the weather magnificent. Under the 

 cumulus where the thunder is growling now, it rains, 

 you may be sure, and the sky looks black. To tin 1 

 people in that region the surroundings present only 

 a rainy appearance, because they are wrapped in 

 clouds; if they were to go elsewhere, l.cymul the 

 clouds, they would find the sky as serene as we have 

 it hero." 



"With a fast horse they could, thru," suggested 

 Kmile, "get I'mm under tin- HmnK leave tin- rain, 

 and conn- into fine \\ c,-it her : as also they could leave 



187 



