AMOUNT OF COLOR IN AMERICAN WATERS.
New England surface-waters have colors ranging from almost nothing up to 2.00. The colors of the public water-supplies of Massachusetts cities have been recorded in the reports of the State Board of Health for some ten years. The figures given were recorded first upon the Nessler standard, and afterwards upon a modification of the same, known as the natural water standard. The figures given are approximately equal to those for the platinum color standard, the relations between the two having been frequently determined by various observers and published in the above-mentioned papers. The accompanying diagram shows the colors in several Massachusetts supplies, as plotted from the figures given in the published reports.
Fig. 18.—Colors of Waters.
(Analyses of the Mass. State Board of Health.)
In Connecticut also the colors of many public water-supplies have been recorded in the reports of the State Board of Health on the platinum color-standard.
The waters of the Middle States, with rare exceptions, are almost free from color. In the Northwest waters are obtained often with very high colors, even considerably higher than the New England waters, and some of the Southern swamps also yield highly colored waters.