diers returning from service in Mozambique.63
For successful use a pair of them were needed, so that, when applied
to a snake-bite, as soon as one became saturated with the venom the
other could be immediately substituted. To have them always at hand,
those natives fortunate enough to own a pair of pedras de cobra carried them about in a little bag.64
A
curious traditional belief is current in some parts of India, notably
in Ceylon, to the effect that the male cobra, during the night, uses a
certain luminous stone to lure its prey and to attract the female. This
is probably the chloro-phane, a variety of fluorite, a substance which
shines with a phosphorescent light in the darkness, and this quality,
quite mysterious in the eyes of the natives, may have induced them to
associate the stone with the snake, the epitome of all subtlety and
cunning. Serpent-stones were supposed to exist in both ancient and
medieval times, and the belief in their existence is widespread among
many races of mankind.
A
chlorophane is also found in the microlite localities of Amelia Court
House, Virginia. The writer made a series of experiments and noted that
some of these specimens emit a phosphorescent light at a low
temperature. The material occurs in Siberia, and Pallas describes a
specimen from this locality. When subjected to the heat of the hand, it
gave out a white light, in boiling water a green light, and when placed
on a burning coal a brilliant emerald-green light, visible at a
considerable distance. Similar phenomena have been observed by the
writer, who has found that very slight attrition, even the rubbing of
one specimen against another in the dark, will produce phosphorescence.86
The real or supposed virtues of the "snake-stones" of Ceylon are detailed at considerable length by the great
H Engelberti Kaempferi, " Amoenitatum exoticarum fasciculi V," Lem-govite, 1712, pp. 395, 396.
• Kunz, " Gems and Precious Stones of North America," 2d ed., New York, 1892, p. 183.
