26 



GENERAL SCIENCE 



condenses into small particles in the air. Sometimes we see little 

 clouds like snowballs forming in the air. These clouds are usually 

 at the top of some rising column of warm moist air which has reached 

 a stratum of cold air. 



Clouds. There are many forms of clouds, the most common 

 being Cirrus, Stratus, Cumulus and Nimbus. 



The subject matter in fine print is to be studied by observation. Compare 

 these old sayings with that which actually happens. If any of the weather 

 forecasts prove true, try to tell why. 



FIG. 13. Stratus. 



Stratus. One-fourth to three-fourths of a mile high. A haze- 

 like cloud which consists of fog in a horizontal stratum. 



A sky covered with clouds need not cause apprehension if the latter are 

 high, and of no great density, and the air is still, the barometer at the same 

 time being high. Rain falling under such circumstances is generally light 

 and not of long continuance. 



Cumulus. One-half mile to 2 miles high. Woolpack clouds. 

 Thick clouds whose summits are domes with protuberances but 

 whose bases are flat. When the cloud is opposite the sun the sur- 

 faces usually seen by the observer are more brilliant than the edges 

 of the protuberances. When the illumination comes from the side 

 this cloud shows a strong dark shadow. On the sunny side of the 

 sky, however, it appears dark with white edges, The true Cumulus 

 shows a sharp border above and below, 



