350 ICE. 



Q. Why do TILES, STONES, and BOOKS often 

 SPLIT in winter ? 



A. Because the moisture (which they 

 imbibed) freezes, and by its expansion 

 splits the solid mass. 



Q In winter time, FOOT-MABKS and WHEEL- 

 RUTS are often covered with an icy NET-WORK, 

 through the interstices of ivhich the soil is clearly 

 seen, WHY does the water freeze in NET-WORK? 



A. The water in these hollows froze 

 first at the sides of the foot-prints : other 

 crystals gradually shot across the water, 

 and would have covered the whole surface, 

 had not the earth absorbed the water 

 before it had time to freeze. 



Q. In winter time these FOOT-MARKS and 

 WHEEL-RUTS are sometimes covered with a perfect 

 SHEET of ice, and not an icy net-work, Why is 



THIS? 



A. The air being colder and the earth 

 harder (than in the former case), the 

 entire surface of the foot-print is frozen 

 over, before the earth can draw the 

 water in. 



Q. Why is not the ice SOLID in these ruts ? 

 WHY is there only a very thin FILM or NET-WORK 

 of ice ? 



