Weather SUtdy 885 



15. If the isobars are near together in a low, it means that the wind 

 is moving rather fast and that there will be a well marked storm. Look at 

 the column giving wind velocity. Was the wind blowing toward the center 

 of the low on the map? If so, does that mean it is coming fast or slow? 

 How does this fact correspond with the indications shown by the distance 

 between the isobars ? 



16. Describe the weather accompanying the approach and passage of a 

 low in the region where your town is situated ? What sort of clouds would 

 you have, what winds, what change of the barometer and thermometer ? 



How to Find the General Direction and Average Rate oj Motion 0} 

 Highs and Lows 

 Observations — i. On the first map of the series of three given, put an X 

 in red pencil or crayon at the center of the high and a blue one at the center 

 of the low; or if you do not have the colored pencils, use some other dis- 

 tinguishing marks for the two. If there are two highs and two lows use a 

 different mark for each one. 



2. Mark the position of each center on this map for the following day 

 with the same mark that you first used for that area. Do this for each of 

 the highs and lows until it leaves the map or until your maps have been 

 used. All the marks of one kind can be joined by a line, using a red line for 

 the red marks and a blue line for the blue marks. 



3 . What do you find to be the general direction of the movement of the 

 highs and lows? 



4. Examine the scale marked statute miles at the bottom of the map. 

 How many miles are represented by one inch on the scale? 



5. With your ruler find out how many miles one area of high or low has 

 moved in twenty-four hours ; in three days. Divide the distance which the 

 area has moved in three days by three and this will give the average velocity 

 for one day. 



6. In the same way find the average veolcity of each of the areas on 

 your map for three days and write down all your answers. From all your 

 results find the average weekly velocity; that is, how many miles per hour 

 and the general direction which has characterized the movement of the high 

 and low areas. . 



Supplementary reading — The Wonderbook of the Atmosphere, Houston, 

 Chapters XI V-XXIII. 



How to Keep a Daily Weather Map 

 The pupils should keep a daily weather map record for at least six 

 months. The observations should be made twice each day and always at 

 the same hours. While it would be better if these records could be made at 

 8 o'clock in the morning and again at 8 o'clock in the evening, this is hardly 

 practicable and they should, therefore, be made at 9 o'clock and at 4. The 

 accompanying chart may be drawn enlarged. Sheets of manila paper are 

 often used, so that one chart may cover the observations for a month. 



Few schools are able to have a working barometer, but observations of 

 temperature and sky should be made in every school. Almost any boy can 

 make a weather vane, which should be placed on a high building or tree 

 where the wind will not be deflected from its true direction when striking it. 

 A thermometer should be placed on the north side of a post and on a level 



