326 BAROMETER. 



Q. What effect does a THUNDER-STORM produce 

 on the weather ? 



A. Thunder is generally preceded by 

 hot weather, and followed ly cold and 

 showery weather. 



Q. What effect does a SUDDEN CHANGE 

 produce on the weather ? 



A. A great and sudden change 

 (either from hot to cold, or from cold to 

 hot) is generally followed by rain within 

 24 hours. 



Q. Why is a sudden CHANGE from HOT to 

 com followed by RAIN ? 



A. The cold condenses the air and its 

 vapour ; which, being condensed and 

 squeezed out, falls in rain. 



Q. Why is a sudden CHANGE from COLD to 

 HOT folloiced by RAIN ? 



A. Because the air is quickly satu- 

 rated with moisture; and as soon as 

 night comes on, the temperature is 

 lowered again, and some of the abundant 

 moisture falls in rain. 



Q. Why is the air quicldy SATURATED irith 

 MOISTURE, when HEAT succeeds rapidly from COLD ? 



A. Because the evaporation (which 



