Religion and Folklore_ (Cambridge, 1911).

[39] Pliny, _Naturalis Historia_, xxix. 52-54.

[40] W. Borlase, _Antiquities, Historical and Monumental, of the County
of Cornwall_ (London, 1769), pp. 142 _sq._; J. Brand, _Popular
Antiquities of Great Britain_ (London, 1882-1883), i. 322; J.G. Dalyell,
_Darker Superstitions of Scotland_ (Edinburgh, 1834), pp. 140 _sq._;
Daniel Wilson, _The Archaeology and Prehistoric Annals of Scotland_
(Edinburgh, 1851), pp. 303 _sqq._; Lieut.-Col. Forbes Leslie, _The Early
Races of Scotland and their Monuments_ (Edinburgh, 1866), i. 75 _sqq._;
J.G. Campbell, _Witchcraft and Second Sight in the Highlands and Islands
of Scotland_ (Glasgow, 1902), pp. 84-88; Marie Trevelyan, _Folk-lore and
Folk-stories of Wales_ (London, 1909), pp. 170 _sq._; J.C. Davies,
_Folk-lore of West and Mid-Wales_ (Aberystwyth, 1911), p. 76. Compare
W.W. Skeat, "Snakestones and Stone Thunderbolts," _Folk-lore,_ xxiii.
(1912) pp. 45 _sqq._ The superstition is described as follows by Edward
Lhwyd in a letter quoted by W. Borlase (_op. cit._ p. 142): "In most
parts of Wales, and throughout all Scotland, and in Cornwall, we find it
a common opinion of the vulgar, that about Midsummer-Eve (though in the
time they do not all agree) it is usual for snakes to meet in companies;
and that, by joining heads together, and hissing, a kind of bubble is
formed, which the rest, by continual hissing, blow on till it passes
quite through the body, and then it immediately hardens, and resembles a
glass-ring, which whoever finds (as some old women and children are
persuaded) shall prosper in all his undertakings. The rings thus
generated, are called _Gleineu Nadroeth_; in English, Snake-stones. They
are small glass amulets, commonly about half as wide as our
finger-rings, but much thicker, of a green colour usually, though
sometimes blue, and waved with red and white."