All old Irish glass has a peculiar depth of tone, but the early glass
of Cork, Waterford, and Dublin is especially distinguished in this
quality. Its steel or grey-blue tone is unique. In this respect there
is very little difference between the wares from the three places, as
they are all characterised by the same mysterious grey colour (supposed
to be caused by impure ingredients). It should be remembered that
the factories in all three localities obtained their materials for
glass-making from the same sources, and that the workmen employed in
them frequently passed from one to another, so that, theoretically,
the metal produced in the three towns should be practically identical.
There are, however, tangible differences in at least a portion of the
glass emanating from the various localities. Thus I have noticed that
some Cork glass has a decided yellowish tinge which Waterford never
has. On the other hand, Waterford glass is often distinguished by a
peculiar cloudy bloom covering the metal, which can be rubbed off,
but will assuredly return. This "bloom" must not be confused with
the milkiness found in decanters, etc., which is caused by wine or
water being allowed to remain in them for long periods. It is quite
different: a soft bloom, exactly like that on grapes, the same colour,
or even darker, than the glass, and often will be found forming a
beautiful band of rainbow hue running round the piece it adorns. I do
not know, for certain, the cause of this appearance, but it probably
originates in some atmospheric action on the lead in the metal. It
is only found on very early dark pieces, and its possession may be
regarded not only as an additional charm of the piece so characterised
but also as a proof of its authenticity. These pieces are most
interesting, but are not always appreciated as they should be. Some
time ago I parted with a magnificent Waterford bowl, beautifully toned
in this manner, only to find a week later that it had been chemically
polished clear and bright, leaving it with not a tithe of its pristine
beauty.
These distinctions of tone and colour which I have ventured to point
out are by no means universal, so that a piece which does not possess
them must not be rejected as spurious _merely on this account_.
Sometimes it is impossible to say from what county a piece came, and
this has led experts to refer to the products supposed to emanate from
the Cork or Waterford factories as "Munster glass." Even this term is
not broad enough, however, for it fails to include the pieces turned
out by the Dublin factories, and these are nearly as likely to be
mistaken for Cork or Waterford wares, as the two latter are likely to
be mistaken for each other. _The blue-grey tinge popularly regarded as
exclusively associated with Waterford glass is quite an erroneous means
of identification, as most of the pieces I have come across, actually
impressed with the mark "Cork Glass Co.," were of this tint._ Dublin
glass, before 1800, was very dark in colour, and the very early pieces
are almost black.
It is very frequently suggested that the chemical action of the air on
old Irish glass may have something to do with the mystery of its unique
coloration; and, strange as it may seem, it is an undoubted fact that
glass does change its tone with the slow lapse of years. I believe this
to be specially so with Irish glass which has remained a long time
in Ireland; and the existence of such phenomena is borne out by the
effect that the atmosphere of Ireland has on old white marble. It may
be argued that, should this be the case, the coloration of Irish glass
may be caused entirely by the atmospheric conditions under which it is
kept, and owe nothing to its local peculiarities of manufacture. This
theory, however, cannot be substantiated, _as English glass does not
appear to be affected by Irish atmosphere to anything like the same
degree as the native metal_. I have frequently seen old Irish dessert
services and chandeliers in which individual pieces which had been
broken had been replaced by facsimiles made in England. These replaced
pieces, however early their origin, do not appear to have changed
colour in the least, and because of this can be readily singled out
among their fellows of native manufacture.