the
traditions of the Arabs, as coming from the mountains of the
Sahara—when sent on an exploring expedition by the Pasha of Egypt. He
mentions having found subterranean mines, capable of allowing four
hundred men to work ; and he likewise found tools, ropes, lamps, and
other utensils. He. judged from the ruins of the architecture of the
temples of a city which he discovered, that they were of Egyptian or
Grecian form, and about one thousand years old.
Among
the church treasures of the ninth and tenth centuries, we find the
emerald, which came into particular notice after the conquest of Peru,
where an emerald the size of an ostrich egg is said to have
been idolatrized by the savage inhabitants. The' emerald was formerly
used as medicine, and was worn "as a preventive against epilepsy.
The
emerald occurs in somewhat depressed six-sided prisms ; the lateral
faces of which are smooth ; the fracture is conehoidal to uneven ; it
is transparent to translucent ; displays double refraction in a slight
degree ; has a vitreous lustre ; is green and emerald-green with its
different shades.
According to Mr. Ebelman, the true emerald is prepared artificially by
