296 THE CHEMISTRY OF CREATION. 



water; the water itself a highly nauseous and 

 disgusting fluid. Water taken from wells in the 

 country generally contains organic matter ; thus 

 presenting a striking contrast to those of the 

 towns, where much more organic matter exists 

 on the surface of the soil, but where the well- 

 water contains chiefly nitrates, not organic 

 matter, properly so called. 



We are therefore led to inquire into the 

 source of this nitric acid in combination. How 

 is it formed, and why formed in the town and 

 not in the country also? The following expe- 

 riments, performed by Dr. Smith, will show 

 that it is actually formed by the simple process 

 of filtration. A jar, open at both ends, was 

 filled with sand, and some putrid yeast, which 

 contained no nitric acid, was mixed with pure 

 water and poured on the sand, allowing it to 

 filter through. Nitric acid was found abun- 

 dantly in the fluid which dropped from this filter. 

 It must have arisen without question, then, 

 from the combination of the nitrogen of the yeast 

 with oxygen, in its passage through the sand. 

 Putrefied meat, treated in the same way, gave 

 the same result. A bottle of strong sulphuretted 

 hydrogen water was poured upon the sand-filter, 

 yet the liquid which dropped through only con- 

 tained sulphuric acid. Water, from a certain 

 pump, exhaled strongly a smell of sulphuretted 



