“I am at a loss to give a distinct idea of the nature of this liquid, and cannot do so without lots of words. Although it flowed with rapidity in all declivities where common water would do so, yet never, except when falling in a cascade, had it the customary appearance of limpidity. It was, nevertheless, in point of fact, as perfectly limpid as any limestone water in existence; the difference being only in appearance. At first sight, and especially in cases where little declivity was found, it bore a resemblance, as regards consistency, to a thick infusion of gum arabic in common water. But this was only the least remarkable of its extraordinary qualities. It was not colourless, nor was it of any one uniform colour- presenting to the eye, as it flowed, every possible shade of purple; like the hues of a mercurial silk. […] Upon collecting a basinful, and allowing it to settle thoroughly, we perceived that the whole mass of liquid was made up of a number of distinct veins, each of a distinct hue; that these veins did not commingle; and their cohesion was perfect in regard to their own particles among themselves, and imperfect in regard to neighbouring veins. Upon passing the blade of a knife athwart the veins, the water closed over it immediately, as with us, and also, in withdrawing it, all traces of the passage of the knife were instantly obliterated. If, however, the blade was passed down accurately between the two veins, a perfect separation was effected, which the power of cohesion did not immediately rectify.“
- From The Narrative of Arthur Gordon Pym of Nantucket (1837) by Edgar Allan Poe.