104 Water 



From the whole of these five acres of green surface, 

 water passes off into the air in the form of vapour, to 

 the amount of seven tons and three-quarters during 

 each twelve hours of clear, dry weather. 



But if this is the quantity returned to the air by a 

 single tree of only moderate size, how large must be 

 the amount received from a wood or forest, containing 

 hundreds or thousands of trees 1 



