WATER. 347 



2ndly It is impregnated with bitu- 

 minous matter, which is hrackish : and 



3rdly It contains many putrid sub- 

 stances, which increase its brackishness. 



Q. Why is NOT KAiN-water SALT, although 

 most of it is evaporated from the SEA ? 



A. Because salt will not evaporate ; 

 and, therefore, when sea-water is turned 

 to vapour, its salt is lejt behind. 



Q. Why does STAGNANT water PUTBEFY? 



A. Because leaves, plants, insects, 

 &c. are decomposed in it. 



Q. Why is STAGNANT water full of WOEMS, 

 EELS, d-c. ? 



A. Because numberless insects lay 

 their eggs in the leaves and plants which 

 float on the surface ; these eggs are soon 

 hatched, and produce swarms of worms, 

 eels, and insects. 



Q. Why are FLOWING waters FBEE/row these 



IMPURITIES ? 



A. 1st Because the motion of run- 

 ning water prevents its fermentation : 



2ndly It dissolves the putrid sub- 

 stances which happen to fall into it : and 



Srdly It casts on the bank (by its 



