PROGRESS OF WATER IXTO THE EARTH. 295 



condition might we not expect the soil to be in 

 which forms the filter through which this decay- 

 ing organic matter penetrates ! Yet, when we 

 come to examine into these matters, " we do not 

 find them," in the words of 'Dr. Smith, "present 

 that exaggerated character which we might sup- 

 pose." It is surprising, on the contrary, to find 

 that organic matters, properly so called, are 

 scarcely, in reality, found in these wells; and, 

 more singular still, the wells nearest to a source 

 of organic matter frequently contain less than 

 others farther removed from the apparent pro- 

 bability of contamination. 



This seems highly paradoxical ; but it admits 

 of being very beautifully and simply explained. 

 The analysis of the waters of the wells in towns 

 shows that they contain a quantity of nitrates. 

 Liebig found nitrates in twelve wells in Giessen. 

 Dr. Smith found the same compounds in thirty 

 wells in Manchester. The wells of London all 

 contain nitric acid in various forms of combina- 

 tion. In an old well at Clerkenwell 148 grains 

 of solid matter were found in a gallon of water ; 

 there was much nitrate of lime among 'other 

 earthy salts. In a natural state, this water 

 ought not to have contained more than about 

 20 grains to the gallon. In a well near Totten- 

 ham-court-road, 130 grains of sulphates, chlo- 

 rides, and nitrates, were contained in a gallon of 



7 P C 



