CHAPTER IV 

 THE WEATHER 



37. Questions for Discussion. 1. Of what value are weather reports 

 to your neighborhood aud to the United States? 2. Why is the air 

 more invigorating after a severe thunderstorm than after a quiet 

 rain? 3. Why does the paper hanger find it warmer near the ceiling 

 than near the floor? 4. Is there pressure of the air against your 

 face when the wind blows? 5. How are low-air pressures and high-air 

 pressures related to winds? 6. What is a cyclone? a tornado? a 

 storm? 7. Why is it that in a tornado trees, houses, and other ob- 

 jects instead of being blown ahead of or out from the storm center 

 are drawn toward it? 8. How do fishermen generally judge when a 

 storm is coming? 9. What are the hot waves which sometimes sweep 

 over great stretches of the Mississippi Valley? What causes them? 

 10. By study of the rainfall map of the United States determine 

 whether there is any relation between the regions of the greatest 

 rainfall and the regions of greatest crop production. 11. Is it of any 

 importance to crops whether the rainfall occurs chiefly in a given 

 part of the year or is distributed over the entire year? 12. How does 

 the United States Weather Bureau determine the amount of rainfall 

 throughout the year in different parts of the country? 13. Is snow 

 counted as part of the rainfall? How is its amount measured? 14. In 

 your locality what are the months of greatest rainfall ? Are these the 

 months in which vegetation makes most growth ? 



38. General statement. Winds and rains come and go in 

 an irregular way that makes it very difficult for us to feel 

 any confidence in our plans if they are subject to disturb- 

 ance by the weather. Weather signs are numerous hi folklore. 

 A number of them are the result of the experience of many 

 years, while others are only the crudest superstition. 



We have rain when there is a cause -for rain ; and the wind 

 blows this way or that, depending upon certain causes. If we 

 are able to discover and understand some of the causes of 



