202 



THE WEATHER 



mometer shelters, or screens, are used by the weather bureaus of 

 all countries. These are placed as nearly as possible at similar 

 heights above sodded ground, where the winds blow freely. 

 Figure 140 shows the American pattern. It has double roof, 

 slatted sides, and is placed 5 to 10 ft. above the ground amid 

 open surroundings. The door opens to the north to avoid 

 the sun's effect when reading the thermometers. In cities, a 

 similar shelter above a flat roof is often the best that can be 

 had. Sometimes for schools a shelter placed just outside 

 a second or third story north window is most convenient, 

 though seldom as good. 



The class should now use the thermometer, barometer and 

 rain gauge in keeping the weather record for one or two 

 months. A home-made rain gauge will do. Inexpensive ther- 

 mometers may be tested and used with their correction 

 cards. Keep the record as shown in the following condensed 

 and convenient form. A part of the Weather Bureau records 

 are kept in similar manner. 



WEATHER RECORD 



1 Altitude 830 ft. 



PROPER HOURS FOR OBSERVING TEMPERATURE 



Reading a thermometer only once a day, in the morning, will 

 make the record lower than the true daily average. Reading 

 it only in the early afternoon will give too high a record. The 

 following four methods have been used: 



