THE OLD - Old Wirral.com

STAINED GLASS IN WIRRAL OLD CHURCHES
duced, consisting mainly of clear glass,
with a thin coating of ruby.
This exceptional method of manufacture
was rendered necessary, because a
sheet of glass, of ruby throughout, would
appear black even in the strongest light.
The colour of ruby glass is due to the
addition of copper oxide to clear glass, but,
owing to imperfections in productions, the
ruby glass of early times was very streaky
in character, a circumstance which rendered
it more suitable for artistic effects.
Probably the most remarkable variety
among the colours of early glass is its
wonderful blue, which, in its deeper
shades, resembled the sapphire. This was
largely used, as was also ruby, for the
ground work of early paintings, the
former, however, being employed more
frequently.
Deep blue glass owed its colour to oxide
of cobalt, its wonderful quality being
probably due to the presence of arsenic, an
impurity frequently met with in cobalt
ores. In its lighter shades, this blue
occurs somewhat rarely, and then usually
only in draperies.
Turquoise blue also occurs, though not
frequently ; it was formed from copper and
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