fo matured Miracles. 



tion. There is probably another power at 

 work to prevent the too ready precipitation of 

 moisture when condensed, and that is the 

 wind. A cloud never stands still, although in 

 some cases it may appear to do so. If we take 

 a stone in our hand and allow it to drop with- 

 out applying any force to it, it will fall di- 

 rectly to the ground. But if we give it an im- 

 petus in a horizontal direction it will travel 

 some distance before striking the ground. If 

 we could give the same impetus to a body as 

 light as a globule of water-dust it would prob- 

 ably travel indefinitely without falling. Dust 

 that would settle directly to the ground from 

 an elevation in still air would travel thousands 

 of miles without falling, before a wind having 

 any considerable velocity. 



Suppose the sun to be shining with intense 

 heat upon a certain area of the earth's surface 

 and the conditions to be right for very rapid 

 evaporation of moisture. The air which is 

 heated close to the ground, being expanded, 

 will rise, together with the invisible particles 

 of moisture, and there will be a column of 

 moisture-laden air continually ascending until 

 it reaches a point in the upper atmosphere 

 where it is condensed into a cloud that takes 

 on the billowy form which in summer time we 

 call a thunder cloud, but which in the science 

 of meteorology is called cumulus, or heap- 

 cloud. If there were no air currents this bil- 



