In Algeria there is a river of genuine ink. It is formed by the union of two streams, one coming from a region of ferruginous soil, the other draining a peat swamp. The water of the former is strongly impregnated with iron, that of the latter with gallic acid. When the two waters mingle, the acid of the one unites with the iron of the other, forming a true ink. We are familiar with a stream called Black Brook, in the northern part of New York, the inky color of whose water is evidently due to like conditions.

— Frank H. Stauffer, The Queer, the Quaint and the Quizzical, 1882