MAGIC STONES AND ELECTRIC GEMS 21
In
seventeenth century Denmark there seems to have been no lack of "magic
stones," for it is related that one day as King Christian II was
strolling along the beach, he picked up a shining pebble by the aid of
which he could render himself invisible at will. Similar power was said
to exist in stones that could be found in ant-hills if hot water were
thrown onto them on St. Walpurgis Day, or St. Hans' Day. The Danes of
the time also shared in the belief that the stone from the lapwing
preserved from illness and sorrow as did the " swallow's-stone" as
well.36
It
has frequently been maintained that the source of pebbles could be
broadly determined by their form and surface ; for example,
well-rounded specimens of fairly uniform size would be classed as
marine pebbles, while river-pebbles would be subangular and usually
flat ; pebbles of glacial origin, on the other hand, would have
faceted, rounded edges, their surfaces being polished and striated.
However, although these rules might hold good in many cases, careful
observation has demonstrated that pebbles of all these supposedly
distinct types can be found among those of marine, fluviatile, or
lacustrine origin. This is explicable by the fact that while the
constant, unhindered action of sea or river would probably produce
pebbles of distinct type, the local conditions often interfere with
this. For instance, on a low sea-coast, with weak wave-action, pebbles
frequently became buried in the sands, thus retaining their form
practically unchanged, and even where the waves are stronger, so that
the pebbles are more or less constantly exposed to their force, it must
be borne in mind that some of these coast pebbles have been swept down
by rivers, or have already been affected by glacial action. In these
cases the force of
"Axel
Garboe, "Kulturhistoriske Studier over -^Melatene, med sœrligt Henblik
paa det 17. Aarhundrede," Kobenhavn og Kristiania, 1915, ρ, 225;
citing a manuscript in the Royal Library at Copenhagen.
