130 NATURE STUDY 



servations for the month. Before allowing them to 

 write this, conduct an oral discussion on generalizations 

 with which they are already familiar, such as the pre- 

 vailing direction and force of the wind and cloud forms. 

 After these facts have been determined and written up, 

 teach them to summarize the temperature in the same 

 way by determining the average temperature for the 

 month, the temperature of the coldest and of the Avarm- 

 est day, -which winds caused a fall in temperature, which 

 a rise. This will necessitate in most instances teaching 

 them w^hat is meant by an average, and how it is found, 

 much earlier than the course in arithmetic provides. 



In the keeping of January's w^eather record, provision 

 should be made for recording the rain or snow fall in 

 inches. The standard rain gauge used by the United 

 States government costs five dollars. It is a cylindrical 

 can, so planned that the amount of the rainfall is multi- 

 plied by ten. 



If this instrument is too expensive, the main purpose 

 may be served by using a tin can with a sharp, even rim, 

 and, in place of the graduated cedar stick which comes 

 with the official gauge, an unvarnished stick, with the 

 tenths of inches marked upon it. 



Whatever the instrument, it should be placed in an 

 open space, and the children should see wdiy this is 

 essential. 



Snow is melted before measuring. 



It is very difficult to get the whole snowfall. Perhaps 

 as accurate a way as any is to cut out wdth the inverted 

 can a circular section of the snow. Melt and measure 

 this. Of course a place must be selected where the snow 

 has not drifted. 



The teacher should get for her ow^n use the daily 



