40 The part that hums away 



stones and grit just under the peat are usually white, all 

 the red material from them having been washed out by 

 the water which has soaked through the peat. Then at 

 the ditch these tiny living things take up the red material 

 because it is useful to them. Peat or " moorland " water 

 can also dissolve lead from lead pipes and may therefore 

 be dangerous for drinking purposes unless it is specially 

 purified. When you study chemistry you will be able 

 to show that both peat itself and moorland waters are 

 "acid" while good mould is not. That is why peat is 

 not good for cultivated plants (see also p. 96). 



Other things besides peat are formed when plants 

 decay under water. If you stir up the bottom of a 

 stagnant pond with a stick bubbles of gas rise to the 

 surface and will burn if a lighted match is put to them. 

 This gas is called marsh gas. Very unpleasant and 

 unwholesome gases are also formed. 



