Note 341 — APPENDIX I. THE SILVER SPRING.

The peculiar hue of the whole St. Johns system of streams has been termed by various travellers a light brown, light red, coffee color, rich umber, and beer color. In the sun it is that of a weak lye, but in the shade often looks as black as ink. The water is quite translucent and deposits no sediment. The same phenomenon is observed in the low country of Carolina, New Jersey, and Lake Superior, and on a large scale in the Rio Negro, Atababo, Temi, and others of South America. In the latter, Humboldt (Ansichten der Natur, B. I., p. 263-4) ascribes it “to a solution of carburetted hydrogen, to the luxuriance of a tropical vegetation, and to the quantity of plants and herbs on the ground on which they flow.” In Florida, the vast marshes and hammocks, covered the year round with water from a few inches to two feet in depth, yet producing such rank vegetation as to block up the rivers with floating islands, are doubtless the main cause. The Hillsboro, Suwannee, and others, flowing through the limestone lands into the Gulf, are on the other hand remarkable for the clarity of their streams. I have drank this natural decoction when it tasted and smelt so strongly of decayed vegetable matter as almost to induce nausea. A fact not readily explained is that while the dark waters of other regions are marked by a lack of fish and crocodiles, a freedom from stinging musquitoes, a cooler atmosphere and greater salubrity, nothing of the kind occurs on these streams.