180 FIE8T YEAR SCIENCE 



When the wind blows spirally and with great violence, 

 sweeping everything before it, it is called a tornado. This 

 is popularly known as a cyclone, but, properly speaking, 

 a cyclone is a very large circular storm. Real cyclones 

 usually do no damage. 



All these storms have a marked effect upon the weather, 

 the changes of which are forecast by the weather bureau. 

 The general weather conditions of a place determine its 

 climate. The climate of any place has a great effect upon 

 plants, animals and man. 



QUESTIONS 



What are the characteristics and principal uses of the three most 

 abundant gases in the atmosphere ? 



How can it be shown that air has weight and exerts pressure ? 



What effect has heat upon the weight and volume of air? 



What effect has pressure upon the weight and volume of air ? 



How do the two kinds of barometer ordinarily used differ in con- 

 struction ? 



Where have you ever observed the effects of adiabatic heating? 



What experiences have you ever had which show that hot air will 

 hold more moisture than cold air? 



How are the light and heat rays from the sun affected by the 

 atmosphere ? 



Name and explain the chief causes that affect the temperature of a 

 place. 



What is the cause of wind and hjow is its velocity measured ? 



How are the winds influenced by the earth's rotation ? 



In going from Boston to Cape Horn through what wind belts 

 would a sailing vessel pass and how would her progress be affected by 

 the winds in these belts? What weather conditions would she 

 probably encounter ? 



At what season of the year would a steam vessel equipped with 

 sails make the best time to India by way of the Suez canal? Why ? 



Upon what does the rainfall of a place largely depend ? 



How is the rainfall of the United States distributed ? 



What is the relation between lightning and electricity ? What is 

 thunder? 



