54 



Experiment No. 5, — Into two glasses of water put some fine clay 

 soil and thoroughly stir the mixture (Fig. 28). Into one glass thus 

 prepared put a spoonful of water-slaked lime and stir thoroughly ; 

 then allow botii glasses to remain quiet that the soil may settle. 

 Kotice in which glass the water becomes clear first and note the 

 appearance of the sediment in each. 



The Moisture iii the Soil. 



In a former leaflet (No. 14) has been given the histor}^ of a thunder 

 shower. We are not told much about the history of the water after 

 it reaches the earth. If we go out immediately after a heavy 

 shower we find little streams running alongside the road. These 



28. — TJie glass of water at the right his received lime and the clay h^s been 



flocculated. 



little streams unite to make larger streams, until finally the creeks 

 and rivers are swollen, and, if the rain was heavy enough, the 

 streams may overflow their banks. In all these streams, from the 

 smallest to the largest, the water is muddy. Where did this mud 

 come from ? It was largely washed from the cultivated fields, and 

 the finest and best soil is certain to start first on its voyage to the 

 valleys or to the sea. If the farmer only had learned better the les- 

 son from nature and kept his fields covered with plants, a large part 

 of the loss might have been prevented. A rain gauge should be kept 

 in every school yard, so that every shower can be measured. It can 

 then be determined easily by the pupils how many tons of rain fall 



446 



