To create this type of decoration blobs of molten glass are dropped on to the
surface of the glass randomly or in a pattern. They were made in a variety of
forms and sizes and left either plain or sometimes impressed with a stamp to
create such forms as ‘raspberries’, which are often a feature on the roemer (see
[not available online]). The ‘claw beaker’ or Rüsselbecher was formed by drawing
out the applied blob of glass into a hollow proboscis, pulling it out and fusing
it to another part of the object; these vessels were made extensively in
northern Europe during the Frankish period (5th–8th century AD). The claws were
sometimes further decorated with trails (e.g. beaker, 6th century; London, BM).
From the medieval period the Rhenish glassmakers decorated beakers with rows of
prunts (e.g. Stangenglas, early 16th century, London, BM; see [not available
online]). Finger cups (Daumenglas) were formed using the same basic principle
but the applied blobs were flattened and then drawn inwards when the glassblower
inhaled through the blow-pipe so that the blobs intruded creating convenient
indentations for the fingers.
(iv) Air bubbles and twists.
Accidental or deliberate inclusions of air in the glass have been used to
decorative effect since glassmaking began. Trapped single or multiple air
bubbles, for example, are one of the simplest methods of decorating a stem. A
‘teardrop’ stem is formed by indenting (pegging) a small depression in the still
plastic rod of glass, which is then engulfed with a gob of molten glass to trap
the air; the ductile rod is then drawn out so that the air forms the shape of a
teardrop. To create a single air-twist stem the same principle is used and the
rod twisted so that the air bubble becomes a helix. To produce a multiple air-twist
stem the top of the malleable glass rod is tweaked with tools to create furrows;
the shape is then immersed in molten glass, which seals in the pockets of air;
the pontil is then securely held while the other end is rotated to create shafts
of twisted air throughout the stem; the process can be repeated many times to
produce more twists. Opaque-white or coloured strands of glass can be imbedded
in transparent glass by rolling a gather of glass over canes set at regular
intervals, marvering and blowing the gather into the desired form. Stems of this
type of decoration were known as cotton-twist stems (see ). The generic term for
decoration using imbedded tapers of opaque-white or coloured glass is filigrana
(filigree) and although first used in Murano during the early 16th century (see
[not available online]), it was probably inspired by the rolled edges used to
decorate mosaic glass made during the Hellenic period in Europe (see Greece,
ancient, §X, 5).
2. Cold-worki
