1 144 Home Nature- Study Course. 



will not be disturbed and a yardstick be placed behind it, you have all the essentials 

 of a barometer, except that the cup, tube and measuring stick are not permanently 

 fastened together. 



Lesson XVI. 



WEATHER MAPS. 



Purpose. — To teach the pupils the use of the weather maps. 

 Material. — Weather maps for three successive days and a wall map 

 of the United States. 



Observations : 



(i). Take the map of the earliest date of the three. .Where was 

 your map used? What is its date? How many kinds of lines are there 

 on your map? Are the explanatory notes on the lower left-hand corner 

 of your map ? Explain what the continuous lines mean. Find an isobar 

 of 30; to what does this figure refer? Find all the towns on your map 

 where the barometer stands at 30 inches. Is there more than one isobar 

 on your map where the barometer stands at 30? 



(2). Where is the greatest air pressure on your map? How high does 

 the barometer stand there? How are the isobars arranged with reference 

 to this region? What word is printed in the center of this series of 

 isobars ? 



(3). What do the arrows indicate? What do the circles attached to 

 the arrows indicate? 



(4). In general, what is the direction of the winds with reference to 

 this high center? 



(5). Is the air rising or sinking at the center of this area? If the 

 wind is blowing in all directions from a center marked high, what sort 

 of weather must the places just east of the high be having? Do the 

 arrows with their circles indicate this? 



(6). Find a center marked low. How high does the barometer stand 

 there? Does the air pressure increase or diminish away from the center 

 marked low, as indicated by the isobars? Do the winds blow toward 

 this center or away from it? 



(7). What must the weather in the region just east of the low be? 

 Why? Do the arrows and circles indicate this? 



(8). Is there a shaded area on your map? If so, what does this show. 



(9). Compare the map of the next date with the one you have just 

 studied. Are the highs and lows in just the same position that they 

 were the day before? Where are the centers high and low now? In 

 what directions have they moved? 



