TREES THAT BUILD CITIES 11 



and then the seeds find their way into the hollow. 

 When the tree is ready to die, the young take up 

 the life-thread, and pushing 1 their way through 

 crevices in the bark, burst the maternal trunk asun- 

 der. Here is a tree which by perfect analogy, like 

 the mammals among animals, shelters its young 

 within its own body. 



We have seen that a tree city has its bad people 

 and its good people citizens who seem to be ruled 

 by the worst of the human passions and inhabitants 

 who have those kindlier if you will, Christian 

 attributes that we all admire. Look a little at a 

 tree city's mechanical organisation. Gas, water, 

 and electricity how are they distributed? 



First, consider water, for it is the most vital. 

 There is no need to lay mains, for nature has pro- 

 vided underground rocky conduits which end by 

 diffusing their contents through the sub-soils. 

 Thirsty roots drink up the water like miniature fire- 

 hydrants. On a warm day a large tree will absorb 

 many tons of moisture. The water is taken up by 

 the roots which have bored deep down into the moist 

 soil ; but how does it get upstairs ? This seems like 

 a simple question at first, but it is a pretty little 

 problem if studied seriously. Scientists studied it 

 many years before arriving at a satisfactory ex- 

 planation. Thirty feet of the rise of water in a 



