Baltimore | | “ | “ | 2.90 | 11.70 | “ Washington |Potomac | “ | “ | 3.50 | 15.70 | “ Oswego | | “ | “ | 2.00 | 15.20 | “ “ |Well | “ | “ | 4.90 | 12.30 | “ Cincinnati |Ohio River | “ | “ | 6.70 | 14.00 | “ “ | “ | “ |Stuntz | .87 | 1.40 |Markley Farm, | | | | | |best condition. “ | “ | “ | “ | 2.45 | 36.42 |Markley Farm, | | | | | |worst condition. “ | “ | “ | “ | 3.15 | 4.37 |Dayton Sand B’ch | | | | | |best condition. “ | “ | “ | “ | 2.33 | 14.24 |Dayton Sand B’ch | | | | | |worst condition. “ | “ | “ | “ | 13.48 | 11.67 |Eden Reservoir, | | | | | |best condition. “ | “ | “ | “ | 12.20 | 42.50 |Eden Reservoir, | | | | | |worst condition. “ | “ | “ | “ | 2.92 | 9.10 |Pump House, | | | | | |best condition. “ | “ | “ | “ | 4.43 | 79.73 |Pump House, | | | | | |worst condition. ------------+-------------+-----+-------+--------+--------+---------------- The Rivers Pollution Commission value the quality of water by the previous sewage or animal contamination, as they term it. This expression is obtained by taking, as a standard of comparison, the amount of total combined nitrogen (which is assumed as 10 parts), in solution, in 100,000 parts of average London sewage. The parts of nitrogen obtained, in the form of nitrates, nitrites, and ammonia, less .032 part of 100,000 for that portion in rain, is that nitrogen derived from animal matter. Animal matters dissolved in water, such as those contained in sewage, the contents of privies and cess-pools, or farm-yard manure, undergo oxidation in lakes, rivers and streams very slowly, but, in the pores of an open soil, very rapidly. When this oxidation is complete, they are resolved into mineral compounds; their carbon is converted into carbonic acid; and their hydrogen into water; but their nitrogen is transformed partly into ammonia and chiefly into nitrous and nitric acids. The following table is a compilation of their analyses: POTABLE WATERS, FROM ANALYSES BY RIVERS POLLUTION COMMISSION, (1874,) (PARTS OF 100,000 PARTS.)