The dimUers in the 8oU 



61 



In one or two days you will see that the water in the 

 U-tube has moved towards the soil flask, showing that 

 some air has been used up by the soil ; further, the lime 

 water has turned milky. But in the other flask, where 

 there is no soil, the lime water remains quite clear. 



This proves, then, that some of the tiny creatures 

 want air just as much as we do. The air reaches them 

 through passages in the soil, through the burrows of 

 earthworms and other animals, or by man's efforts in 

 digging and ploughing. 



Fig. 28. 

 A bag of soil is fixed into a flask containing lime 

 water. In a few days some of the air has 

 been used up, and the lime water has turned 

 milky 



Now try the experiment with very dry garden soil : 

 little or no change takes place. As soon as you add 

 water, however, breathing begins again, air is absorbed 

 and the lime water turns milky just as before. Water 

 is therefore wanted just as much as air. 



If you had very magnifying eyes and could see 

 things so enlarged that these little creatures seemed to 



