The following tabulation shows the relative purity of the water supply of several American cities, as determined by Prof. A. R. Leeds, in June, 1881:-- ----------+-------+------------------------------------------------------- | New |Brooklyn. | York. | +-------+--------------------------------------- | | |Jersey |Philadelphia. | | | City. | +-------+----------------------- Parts in | | | | |Boston.|Washington. 100,000 | | | | | | +--------------- | | | | | | |Rochester. | | | | | | | +----------- | | | | | | | |Cincinnati. | | | | | | | +---+ | | | | | | | | ----------+-------+-------+-------+-------+-------+-------+-------+------- Free | | | | | | | | ammonia. | 0·0027|0·00075|0·00475| 0·001 |0·01325| 0·006 | 0·0114| 0·0115 Albuminoid| | | | | | | | ammonia. | 0·027 |0·00825|0·0427 | 0·018 |0·0605 | 0·027 | 0·023 | 0·024 Oxygen | | | | | | | | required.| 0·81 |0·413 |0·95 | 0·46 |1·77 | 0·600 | 0·790 | 0·860 Nitrites. | None |None | None | None | None | None | None | None Nitrates. | 0·8325|1·2025 |0·9065 | 0·6845|1·2395 | 0·8325| 0·629 | 0·740 Chlorine. | 0·350 |0·550 |0·235 | 0·3000|0·315 | 0·270 | 0·195 | 0·805 Total | | | | | | | | hardness.| 3·300 |2·270 |3·200 | 4·400 |2·100 | 4·800 | 5·500 | 6·400 Total | | | | | | | | solids. |11·800 |6·000 |9·300 |14·300 |8·500 |11·500 |10·000 |16·200 Mineral | | | | | | | | matter. | 5·000 |5·000 |3·400 | 6·000 |2·000 | 5·500 | 4·000 | 9·000 Organic | | | | | | | | and | | | | | | | | volatile | | | | | | | | matter. | 6·800 |1·000 |5·900 | 8·300 |6·500 | 6·000 | 6·000 | 7·200 ----------+-------+-------+-------+-------+-------+-------+-------+-------