332 SNOW. SLEET. 



of air below freezing point, some of the 

 vapour is squeezed out, and frozen into 

 snow. 



A few years ago, some fishermen (who wintered at 

 Nova-Zembla), after they had been shut up in a hut for 

 several days, opened the window, and the cold external air 

 rushing in, instantly condensed the air of the hut, and the 

 vapour (which was squeezed out) fell on the floor in a 

 shower of snow. 



Q. Why does SNOW fall in WINTER time ? 



A. Because the sun's rays are too 

 oblique to heat the surface of the earth ; 

 and (as the earth has no heat to radiate 

 into the air) the air is very cold. 



Q. What is SLEET? 



A. When flakes of snow (in their 

 descent) pass through a bed of air above 

 freezing pointy they melt ; and fall to the 

 earth as half-melted snow or sleet. 



Q. What is the USE of SNOW ? 



A. To keep the earth warm, and to 

 nourish it. 



Q. How can snow keep the EARTH WARM ? 



A. Because it is a very bad conductor; 

 in consequence of which, the earth which 

 is covered with snow, very rarely descends 

 below freezing point, even when the air 

 is 15 or 20 degrees colder. 



