VARIETIES OF VENETIAN GLASS—EARLY LITERATURE
The history of modern glass begins, as I have said, with the famous
Venetian _cristallo_ of the sixteenth century. Many other varieties
were made at this time, but it was the absolutely colourless and
transparent glass, capable of being blown to extreme thinness and then
worked into every variety of form, that above all established the
European reputation of the Murano glass-workers. Before long, in nearly
every country of Western Europe, the old methods of working were
falling into disuse; and by the aid of skilled workmen who were tempted
away from Murano, or, failing that, were hired from the rival glass
furnaces of L’Altare, the attempt was made to imitate this clear white
glass of Venice.
We have, then, in this _cristallo_ the typical glass of Venice, and
here more than in any other group, whether of earlier or of later date,
we find a family of glass of which the artistic merit depends directly
upon the skill of the glass-blower, rather than on that of the
enameller or engraver. In the simpler and earlier specimens, an
undeniable charm is derived from the extreme tenuity of the
material—there is an evanescent and almost ghostly air about the
‘diaphanous, pellucid, dainty body’[147] of not a few of these glasses.
Although entirely free from any positive colour, there is often a
certain tendency to greyness in the metal, and this is increased to a
misty cloudiness when the surface has been attacked by atmospheric
influence, as is not unfrequently the case with glasses that have been
long exposed to our damp English climate.
[Illustration:
_PLATE XXXI_
VENETIAN GLASS
FLOWER-VASE OF COLOURLESS GLASS WITH BLUE THREADING AND STUDS]
There is little change or development to be observed in the glass of
this character made at Murano during the sixteenth and seventeenth
centuries, nor is it always safe to regard contorted shapes and
elaborate decorations as necessarily a sign of a late origin. This
caution is confirmed by an often quoted passage from Sabellico, the
learned librarian of St. Mark’s and historian of Venice; it is from a
Latin work, _De Situ Venetæ Urbis_, written about 1495. We can form
from it some idea of the wonderful variety of the outturn from the
Murano glass-works at that time, and of the elaborate shapes that were
already given to the vessels. When we pass, says Sabellico, from Venice
to the suburb of Murano, we are struck by the grandeur and size of the
buildings; it appears from afar as a city, extending for a mile in
length. The island owes its chief renown to its glass-works. It was a
famous discovery to make glass that should vie with crystal in
clearness. Since then the nimble wit of the workmen and the
never-resting care to find something new have led them to apply to the
material a thousand various colours and shapes without number. Hence
the _calices_, the flasks, the _canthari_, the ewers, the _candelabra_,
the animals of every race, the horns, the beads (_segmenta_), the
bracelets, etc. etc. So far Sabellico—the good man is, I am afraid,
more concerned with his latinity than with the matter in hand: but this
is a weakness that he shares with more than one writer of this time. He
goes on to speak of the ‘Murrhine vases’ made at Murano, of which the
only fault is their cheapness; all these marvels had the Venetian
galleys brought before the eyes of the nations, so that, wondrous to
say, by familiarity they had become as things base and common.
In the means adopted by the Venetians to adorn their _cristallo_ we are
at times taken back to Roman methods. The handles, often of blue glass,
and the stringings and frillings that surround the body are applied
hastily but skilfully by the light hand of the workman. This kind of
ornament reached its completest development in the tall beakers and
vases with handles that took the form of wing-like excrescences. These
‘winged beakers’ were afterwards copied and the forms exaggerated in
Germany and in the Netherlands, where they were held to be especially
characteristic of the now fashionable glass of Venice.
It is certainly remarkable how little this Muranese glass as a whole
reflects the glorious Venetian art of the _cinquecento_. Apart from
some of the earlier enamelled and gilt examples and from the simpler
forms of the pure thin _cristallo_, we can find among it little that is
quite satisfactory from an artistic point of view. Much even of the
sixteenth-century glass is merely fantastic, and appeals only to
childish tastes. The bulk of it was probably made for foreign markets,
for the dull northern barbarian, whose attention had to be caught by
something new and extravagant.
Little heed is paid to this more elaborately decorated glass by the
great contemporary painters. In fact, I can find no example of it in
their works. When glass is introduced, it is invariably of the simplest
description. In the big altar-pieces of Giovanni Bellini, of Cima, or
of Carpaccio, the glass lamps that hang from the roof are in the form
of little conical cups of plain outline. Amid all the elaborate
_staffage_ of Crivelli’s pictures, the lily on the table or ledge
beside the Virgin stands in a little cylindrical beaker of glass, for
all the world like a modern tumbler.[148] So in the next century we may
search in vain in the pictures of Titian or of Veronese for elaborate
examples of Venetian glass. In the banquet scenes of the latter
painter, the wine indeed is served from graceful decanters with tall
necks and globular bodies, and is drunk from tazza-shaped goblets of
glass,[149] but on the _credenza_ or buffet at the side, the gold and
silver plate is never relieved by examples of our material.
[Illustration:
_PLATE XXXII_
VENETIAN GLASS
OPAQUE WHITE WITH GILT SCROLLS. EARLY SIXTEENTH CENTURY]
A curious account of a banquet given at Mantua, on the occasion of the
marriage of the Marquis, is quoted by Mr. Nesbitt from a contemporary
writer. There was, we are told, on this occasion such a display of
‘_diversi bicchieri, carrafe, e giarre ed altri bellissimi vasi di
cristallo di Venezia, che credo vi fussero concorse tutte le botteghe
di Morano!_’ And there was need of this store, he adds, seeing that
after they had drunk, the guests proceeded to break the glasses they
held in their hands ‘_per segno di grande allegrezza_.’[150] We are
reminded of the feast described by Joinville, though in that case the
glasses were swept off the table by the well-aimed Bible of one of the
guests (see p. 136).
I shall now have to pass in rapid review the principal varieties and
applications of the glass made at Murano in the sixteenth and
seventeenth centuries.
The Frosted or Crackle Glass is perhaps the simplest modification of
the pure _cristallo_. To produce this, the _paraison_ is plunged
rapidly into cold water, and after reheating to the necessary degree,
but not beyond, it is worked into the desired form. A similar effect is
at times produced by rolling the molten _paraison_ upon fragments of
crushed glass. I have spoken in the introductory chapter of certain
rare cases where a minute fissuring has been set up in the substance of
the glass. This true crackle is probably in all cases the result of a
subsequent structural change.
_Latticinio_, _Lattisuol_, or _Lattimo_ are names given by the
Venetians to a milk-white opaque glass. White enamels were freely used
in the fifteenth century, but the earliest known specimen of Venetian
glass, the whole body of which is rendered opaque by the presence of
oxide of tin (_calcina di stagno_)—the _vetro bianco di smalto_ of the
early writers[151]—can hardly be older than the beginning of the next
century.
The spherical vase (Slade, 402) formerly in the possession of the
Marquis D’Azeglio, is an exceptionally beautiful example of this
milk-white glass (Plate XXXII.). The gilt scrolls harmonise well with
the slightly warmish ground, and were it not for the rudely executed
mermaids on either side, an Eastern origin might well have been sought
for this quite exceptional piece; in fact, I do not know of any other
specimen of undoubted Venetian glass so distinctly Persian in character.
In the Museo Civico at Venice is a flask (_circa_ 1530) of this
_lattimo_ glass, about five inches in height, decorated in blue, with
allegorical subjects. Although somewhat rudely executed, the painting
is masterly in style, and may be compared to that on the best
contemporary majolica (Plate XXXIII.). At a first glance this little
vase might be taken for an example of Medici porcelain, and indeed we
must bear in mind that all through the sixteenth century attempts were
being made in Venice to imitate the porcelain of the Far East, more
especially the plain white and the blue and white wares which were
already arriving at Venice in considerable quantity.
This _lattimo_ glass came much into favour for a second time early in
the eighteenth century; it was at that time often decorated in colours
in a pseudo-Japanese style. This later milk-white glass is once more
closely associated with the attempts then again made at Venice, as in
so many other countries, to imitate the porcelain of China and Japan.
This had indeed, before the end of the previous century, been in a
measure accomplished in France by means of a soft paste, in the
composition of which a glass-like frit played an important part. At a
still later time this _lattimo_ glass was even painted in monochrome,
in imitation of our early printed Worcester porcelain!
[Illustration:
_PLATE XXXIII_
PILGRIM’S BOTTLE; DESIGN IN BLUE ON LATTIMO GLASS
VENETIAN, EARLY SIXTEENTH CENTURY]
Closely based upon this _latticinio_—for the threads in a vast
majority of cases are of an opaque white—is the famous _Vetro di
Trina_ or lace-glass. At the beginning of the last century the art of
making this net-work decoration appears to have almost died out, but in
the thirties and forties it was revived by Domenico Bussolin, and when
later on more interest began to be taken in the Murano glass, it was to
this _vetro a reticelli_ that at first most attention was given. The
details of the manufacture were described and illustrated by the
well-known director of the Choisy glass-works, M. Bontemps (_Exposé des
moyens employés pour la fabrication des verres filigranes_, 1845).
There is, however, a simpler and perhaps easier application of these
bands of _lattimo_, in which they are applied in a series of festoons
to the surface. In this case the opaque white enamel appears to have
been laid on to the _paraison_ at an early stage and dragged into
crescent-shaped waves, so as to resemble closely the decoration of the
little flasks of coloured glass from Egyptian and early Greek tombs—to
those later examples more especially, from Rhodes and Cyprus, on which
the colours are only applied to the surface (p. 37), the resemblance in
technique is very close. There are many interesting specimens of this
festooned _latticinio_ in the British Museum. In the case of the little
_biberon_ (Slade, No. 628) the festoons are worked into a palm pattern,
identical with that often found on the little primitive vases.
I shall not attempt to follow in detail the manner of preparation of
the true _vetro di trina_,—suffice to say that it is built up of a
number of juxtaposed rods; these rods are arranged perpendicularly,
side by side, so as to form a hollow cylinder, and into the midst a
small vesicle of molten glass is inserted; to this the rods adhere, and
the whole mass is then worked into the desired form. The rods
themselves—they are similar to the _canne_ supplied to the
_suppialume_ workers (p. 187)—may be either of opaque or clear glass,
or they may be formed of elaborate combinations of the two (_canelle a
ritorto o merlate_); the most complicated patterns are thus obtained.
When two series of these rods are arranged to cross one another at an
angle, we get a reticulated pattern, and within the _reticelli_ thus
formed a bubble of air may be caught up. There is, indeed, little
opportunity for finding in this kind of work any free play for the
decorative feeling of the artist, and the result of all these ingenious
combinations of crossings and interlacings is only too often to give a
tame and machine-made air to the finished vase or tazza.
The Opalised Glass, the _Calcedonio_[152] of the Venetians, is obtained
by adding the same materials as in the case of the _latticinio_, but in
very small proportions: it stands to the latter as weak milk and water
to pure milk. In practice, I believe, the opalescence is often given by
the addition of phosphate of lime in the form of bone-ash, sometimes,
perhaps, by arsenious acid.[153] Pale blue by reflected light, it takes
various orange and yellow tints when the light is transmitted through
it. Such a vessel as the cylindrical goblet and cover of thick
_calcedonio_ in the Waddesdon Room at the British Museum, with a design
in high relief representing the Triumph of Neptune, must have been cast
in a mould.
We now come to certain varieties of glass which were much admired at
one time, but are now little in favour. The aim, it would seem, in this
class, as in the case of the old Roman prototype, was to imitate
various kinds of precious stones and marbles. But the Venetians showed
here little of the restraint of their classical predecessors, so that
on the whole the colours, where not crude, are huddled together in
muddy compounds.
An opaque red glass resembling jasper was probably known at Murano as
early as the fourteenth century. In an inventory of the property of the
Duke of Anjou (_circa_ 1360) there is mention of a ‘_pichier de voirre
vermeil semblable a Jaspe_.’ So in the next century, Charles the Bold
possessed ‘_Ung hanap de Jaspe garni d’or, à œuvre de Venise_’—to
judge from the expression used this beaker was also of glass.[154]
Already in a Milanese manuscript of 1443 (described below) there is a
formula given for making _schmelz_ by means of a mixture of certain
salts of silver, iron, and copper, and before the end of the century we
have Sabellico’s complaint that the modern murrhine glass was becoming
far too common (see page 201); so that, on the whole, this family of
marbled glass is, perhaps, as old as any other Venetian glass of which
we have specimens. The examples, however, that have survived appear to
be mostly of a somewhat later date. We find imitations of both classes
of the Roman _millefiori_—the tints, however, are generally crudely
matched—and especially several varieties of marbled glass with
contorted veins of many colours. The schmelz _par excellence_ of the
Venetians (the German name would seem to point to a northern origin) is
an irregularly veined and mottled mass, a somewhat unpleasant
combination of bluish-green and purple tints, calling to mind certain
kinds of slag—indeed it may have originally been made in imitation of
some such substance. There are a few exceptionally fine early examples
of this schmelz at South Kensington. Notice above all the spherical
vase from the Castellani collection with _cinquecento_ mountings and
serpent handles of copper gilt; the greenish-yellow and pale blue tints
are in this case harmoniously blended. To judge from the form of the
bowl and stem, the cup of finely marbled schmelz at Hertford House
cannot be dated much later than 1500. In this case, and probably in
others also, the marblings are only on the surface; the interior is of
a uniform greyish-green colour.
Of scarcely less importance is the splashed ware for which we can again
find a Roman if not an Egyptian prototype. The splashes of enamel of
various colours must have been scattered over the _paraison_ at an
early stage, for they have had to follow the changes of form given to
the surface in the shaping of the vessel: we see them stretched out at
the neck on the little burette in the Slade collection (No. 783). This
splashed glass was much admired by the French and successfully imitated
by them.
Something should be said of the painted Venetian glass of the
seventeenth and eighteenth centuries. I say ‘painted,’ for such it is
in general effect, although the pigments have probably in most cases
been subjected to some kind of firing. The very poverty and dulness of
the colours are indeed a proof of this; the artist’s palette has been
subjected to the exigencies of the enameller’s muffle. We find
landscapes with classical figures and _amorini_ painted on the lower
surface of bowls and rondelles (_tondi_). In the Dutuit collection, now
housed in the Petit Palais at Paris, is a circular dish some fifteen
inches in diameter, painted on the under surface, so as to be viewed
through the glass; the subject, a dance of cupids, is treated in an
exceptionally fine style and can scarcely be later than the middle of
the sixteenth century. In many cases these designs have been added to
Venetian glass by non-Venetian, sometimes by northern hands. This kind
of painting or enamelling is, however, very subject to injury by use,
and doubtless for this reason it is sometimes protected by a second
sheet of glass. We have in such painted dishes a variety of the
so-called _verre églomisé_ to which reference has already more than
once been made.
The Venetians at times drew designs on their glass with a diamond.
There are some examples of this in a good _cinquecento_ style in the
Slade collection; but this work was confined to the pure scratched
line, and even shading was not much used. It was not till the
eighteenth century that they began to copy the later German methods of
deep engraving and cutting with the wheel.
The British Museum has lately acquired a square plaque of clear thick
glass; at the back, in deep intaglio, is the portrait of a Doge, who,
on the ground of the letters A. G. on either side of the head, may be
identified with Andrea Gritti (1523-1538).[155] The late M. Piot has
extracted from a fifteenth-century treatise on architecture by Antonio
Averlini a dialogue between two artists upon some curious applications
of glass. We hear of _cristallino_ plaques with figures carved on the
lower surface, so as apparently to stand out in relief—a description
which would apply well enough to this _piastra_.
There is no more troubled story in the history of glass-making than
that of the manufacture of MIRRORS at Murano from the fourteenth to the
eighteenth century. We have seen in the early days, when these mirrors
were backed with lead (p. 138), that the Germans had already become
experts in this department. More than once in the Venetian archives
there are references to the secret methods of these _Todeschi_. In a
petition of 1503 there is mention of a plan for making good and perfect
mirrors, a precious secret unknown except to certain Germans. It is
impossible to resist the suspicion that there is here a reference to
the cylinder process, which, as we have seen, was already known to
Theophilus (p. 129); by this process it would have been possible to
produce a fairly large and comparatively flat sheet of glass. The
Venetians, on the other hand, probably continued to a late period to
use the old method of ‘spinning’ or ‘flashing.’[156]
It was only after the middle of the sixteenth century that the
mirror-makers, the _specchiai_, formed themselves into a separate
corporation; but in this guild were included, it would seem, the makers
of the so-called mirrors of steel.[157] Thus we find that in 1574, one
Francesco Zamberlan, who only two years before had taken out a patent
for his ‘_specchi d’acciaio_,’ was admitted to the new guild on the
ground of his special knowledge. Those engaged in the polishing—the
_lustratura_ and _spianatura_—of both materials, glass and metal, were
also members of the guild.
For us the interest in these mirrors lies rather in the framing. We
find the new corporation early engaged in quarrels with the painters
and with the workers in tarsia, mother-of-pearl, and coral (_i
miniatori_, _i marangoni_, _e muschieri_), who found employment in
decorating the frames.
For a time, no doubt, the Venetian mirrors held their own, but before
the end of the seventeenth century the French, thanks to the energy of
Colbert, had not only learned all their secrets, but by an entirely new
method—namely by a process of casting or founding, and subsequent
rolling and polishing of the glass plates—were able to meet the demand
for the large mirrors that were now regarded as indispensable in a
Louis-Quatorze salon. But these ‘_glaces de St. Gobain_’ are of an
entirely different nature from the exquisitely framed little _lustri_
with which we are now concerned. Unfortunately, as far as I know, there
are no characteristic specimens of these _cinquecento_ mirrors—at
least of those in which glass forms an important element in the frame
as well—in any of our public collections. For fine examples of such
work we must go to the Louvre or the Hôtel de Cluny. It will be noticed
that the margin of the glass is invariably bevelled, thus forming a
transition to the elaborate framing. These _cinquecento_ Italian
mirrors were extensively copied, and this at an early date, both in
France and at Nuremberg.
In spite of the heroic efforts made by the authorities in the late
seventeenth and in the following century to introduce the new methods
of working glass at Murano, the Venetians failed to maintain their
position. It was only in the more conservative Eastern markets that the
demand for their mirrors was kept up; even to-day, in Syria or in
Persia, these Italian glasses may not unfrequently be seen in private
houses and even in mosques.
Another characteristic application of the glass of Murano was to the
elaborate chandeliers that formed so important a part in the decoration
of the reception-rooms of a Venetian palace in the seventeenth century.
In these the metal framework is completely hidden by a thick foliage,
as it were, of glass—frequently of the opalescent _calcedonio_—amid
which the tall wax candles spring up here and there. M. Gerspach extols
the decorative value of these chandeliers:—‘_Le soir, le lustre de
Venise allumé est un rayonnement harmonieux sans reflets discordants;
le jour, stalactite ciselée, il égaye l’appartement comme une note
claire et joyeuse_’ (_La Verrerie_, p. 173).
In the eighteenth century the contorted forms, imitating leaves and
flowers, were replaced by pendent discs of colourless crystal, cut,
polished, and often facetted. Of these later chandeliers there is a
splendid series, whether of Venetian origin or not I do not know, at
Hertford House. Such chandeliers were known in England in the
eighteenth century as ‘lustres.’[158] They are above all numerous in
German palaces, and most of the glass is probably of German or Flemish
origin. But of the earlier type I cannot find a single example in any
of our public museums.[159] The manufacture, however, has been revived
at Murano, and chandeliers of this class, with no claims to antiquity,
may often be seen in private houses both at home and abroad. The spread
of electric lighting has given a stimulus to work of this kind, for the
corolla-shaped shades that so often accompany our incandescent lamps
have, in most cases, obviously been modelled upon the glass of the old
Venetian chandeliers.
The glass-workers of Murano were a conservative body; their work was
based upon secret processes and rule-of-thumb formulas. The elaborate
division into different _arti_ or corporations, each governed by its
separate _mariegola_, made it excessively difficult to introduce any
radical changes into the methods of work. It is quite pathetic to
observe the efforts of the comparatively enlightened governing body,
the _conservatori alle arti_, who in the last years of the republic
attempted to introduce the new processes that were revolutionising the
glass industry in the north of Europe. We find reports signed by great
names—Morosini and others—recommending the introduction of English
machinery, and drawing up plans for the cultivation of the _Salsola
soda_ on the islands of the lagoons. Little attention apparently was
given to the artistic side by these reformers. One of the last names in
the long list of the Murano glass-makers is that of Giuseppe Briati,
famous for the purity of his _cristallo_; he excelled, too, in the
designing and the execution of the _vetro di trina_, and Lazari
declares that much of the ‘lace glass’ in our collections attributed to
the _cinquecento_ belongs rather to him or to his school.[160] Briati
in 1739 was allowed to set up a furnace in Venice itself for the
preparation of his _cristallo_, the first time for more than four
hundred years that such a permission had been granted. It is of this
Briati that we are told that his glass found a place on the _credenza_
or buffet at the public banquets of the Doge, beside the gold and
silver plate. This would appear to have been an innovation (see above,
p. 203) introduced with the special aim of encouraging the declining
industry. An exception was again made in favour of one Giorgio
Barbaria, who so late as 1790, in the parish of the Gesuiti,
manufactured bottles by a new English method. But as a French writer
somewhat naïvely puts it—‘_ce genre ne prête guère à la fantaisie_.’
Before this time the Venetians had yielded to the new fashion of the
day, and were making cut and engraved glass more or less after German
or Bohemian models. Of this class were the _trionfi di
tavola_—trophies of glass for the decoration of the dinner-table—as
well as the gigantic chandeliers known as ‘_ciocche_.’ To such
productions the artistic work of the time appears to have been
confined. Of the first there is a fine specimen from the Casa Morosini
set out in the centre of one of the rooms in the Museo Civico at
Venice. I have already mentioned the chandeliers of cut glass. They
played an important part in a _rococo_ interior.
After the occupation of Venice by the French in 1797, the Directory
attempted unsuccessfully to transplant the manufacture of beads
(_marguerites_) to Paris. It is significant that they regarded this as
the most important part of the glass industry. The corporations or
_arti_ were finally abolished in 1806.
During the ensuing thirty years the manufacture of glass was at the
lowest ebb. There was, however, a first revival about 1838, which is
associated with the name of Bussolin. But it was the energy and skill
of a lawyer from Vicenza, Antonio Salviati, with the financial
assistance of certain English enthusiasts for the art, Sir Henry Layard
and Sir William Drake, in the first place, that led, not long after the
middle of the century, to the furnaces of Murano again turning out
something beyond window-glass and beads.
From the technical side Venetian glass belongs essentially to the
Mediterranean family—the art was possibly learned in the first
instance from the Byzantine Greeks. But it is probably as a consequence
of their intercourse with the coast of Syria, the old home of glass,
that the Venetians acquired at so early a date a pre-eminent position
as glass-workers. Like that of their predecessors, theirs was
essentially a soda glass. What distinguished it was, above all, its
total freedom from colour; the Venetians were the first, at least since
Roman times, to make an absolutely clear white glass. This result they
obtained not only by care in the selection of their materials,
especially in the source of the silica, but also by an early mastery of
the use of manganese, ‘the glass-maker’s soap.’ The Venetian glass
excelled again in its working qualities, in the extreme ductility which
it maintained through a wide range of temperature. This property was in
a measure due to the large quantity of alkali which entered into its
composition. On the other hand, this excess of soda has led at times to
a rapid tarnishing of the surface, visible above all in our damp
climate.
[Illustration: _PLATE XXXIV_
VENETIAN GLASS
ABOUT 1500
1. PLATE, ENAMELLED AND GILT—ARMS OF DELLA ROVERE FAMILY 2. TAZZA,
ENAMELLED WITH COAT OF ARMS]
But it is to the works of the contemporary Italian writers that we had
better turn for information on these practical points. These are of two
classes:—1st, Works of some literary pretension which contain chapters
on the glass of Murano for the information of the general public. 2nd,
Technical treatises, consisting for the most part of formulas for the
use of the glass-maker. To the first class belong Fioravanti’s remarks
on mirrors, which we have already quoted. Biringuccio, the Sienese, in
his treatise on _les arts du feu_ (_De la Pirotechnia_, Venice, 1540),
has a chapter on glass (Bk. II. cap. xiii.). He tells us that the
Venetians made glass from the ashes of _chali_, an herb that grows in
Syria and also near Magalone, in the south of France (the lagoons of
Maguelonne, near Cette). In the place of this _chali_ the ashes of fern
or of the mysterious _duznea_ may be used. One part of the lixiviated
ash is mixed with two of the _cogoli_, the clear white pebbles found in
the bed of certain streams. To these materials a small amount of
manganese is added, and the whole melted in a reverberatory furnace to
form a substance known as _fritta_, already a kind of glass, but ‘_mal
purgata_.’ The glass furnace is then described in some detail: it is
made to hold eight crucibles (_conconi_), each three-quarters of a
_braccio_ (say fifteen inches) in height. These _conconi_ are made with
_terra di Valencia_, and are first well dried and annealed over the
fritting-hearth. We are told how, after melting in these pots, the
viscous substance is collected at the end of a hollow rod of iron,
turned and returned upon the marver to unite the mass together, and
then by blowing down the tube extended to form a vesicle. This
‘_vescicha_’ is now whirled round the head of the workman to lengthen
it, or it may be pressed into a mould of bronze (‘_in un cavo di
bronzo_’). It is now transferred to another rod of iron (the
_pontella_, though the word is not used), worked up in various ways,
and cut with shears. The handles and feet are added, and the vessel may
be decorated by enamelling or otherwise.[161]
_La Piazza Universale di tutte le professioni del Mondo_, by Tommaso
Garzoni of Bagnacavallo, was, to judge from the numerous editions
issued, a very popular work in its day. The copy before me, not by any
means the first edition, is dated Venice, 1585. It contains a chapter
entitled ‘_De Vetrari, o Biccherari, Occhialari e Fenestrari_.’ The
superiority of the glass of Murano, ‘_luogo amenissimo e delitiosissimo
presso a Venetia_,’ he attributes to the saltness of the water, to the
absence of dust, so detrimental to the work, and to the abundant supply
of wood which gives a most beautiful and clear flame. Besides, it is
only at Murano that they know how to prepare the soda with which the
beautiful _cristallo_ is made. That made from the herb _ugnea_ (cf. the
_duznea_ of Biringuccio) or from fern, produces a yellow and brittle
glass,—the inferiority of the potash glass is here indirectly
indicated. Among the long list of the vessels made at Murano we find
_zuccarini a reticelli_ or _a ritortoli_, interesting as an early
mention of lace glass. The word _zuccarino_, literally a basin for
sweets, is used as a general name for covered bowls or dishes. We then
have the account (already quoted) of the preparation of _latticinio_,
and also of a glass made up of fragments of _canne_ of various colours,
a kind of _millefiori_, in fact. There is, he tells us, nothing
imaginable in the world that these Muranese cannot make with
glass—castles even with towers, bastions, walls, and cannon. ‘_Come
nell’ Ascensa di Venetia talvolta s’ è vista_,’ he continues. This
refers, I think, to the display of masterpieces of glass in the
procession on Ascension Day.
Garzoni, we must remember, is in this book in the first place concerned
with the various trades and professions of his time, and he takes us
next to the _occhiolari_, the makers of spectacles, who ply their trade
in the Merceria, and finally to the _Finestrari_ or _Vetriari_, who
with marvellous rapidity fit into frames of lead ‘_certi occhi di
vetro_’ made at Murano. We see from this that the old bull’s-eye glass
was still in general use.
I must now, in conclusion, say something of the other class of writers,
those who, without any literary pretensions, claim to disclose the
secret processes and formulas of the glass-workers. These men are the
successors of Theophilus and of the compilers of the early alchemistic
treatises of which I have spoken in a previous chapter. It is
noticeable that not one of these men, as far as we know, was a
Venetian; indeed in every case, if the writer is not a Florentine
himself, it is from Florentine libraries and archives that his works
have been extracted.
Cennini was essentially a writer of this class, but in his _Trattato
della Pittura_ there are only a few casual references to glass. The
three little treatises found by Gaetano Milanesi in the Florentine
archives, and published by him in 1864, are chiefly concerned with the
preparation of glass for mosaics. They may probably be attributed to
the first half of the fifteenth century, and we thus have in the
recipes which fill these books the earliest documentary evidence for
the composition of Venetian glass. I will quote from the first of these
little works a section (xxiii.) which treats of ‘the placing of glass
on the surface of glass.’ The writer, it should be noted, is concerned
with the preparation of the _piastre_ or slabs from which were cut the
little cubes for mosaic work; this question of the various ways in
which a leaf of gold may be included between two sheets of glass is one
which has already interested us.
‘♃ The glass to be about as thin as an eye-glass. Cut the leaves of the
gold to the length of the glass, and put the gold upon the glass with
white of egg; then place above this gold the other upper glass, and dry
the whole. Then put them in the small ovens (_fornelli_), and let them
be on a level so as not to slope, in order that the glass may not run.
When they have become red-hot, load them with an iron so that they may
grow together and unite. Then place them over the arch of the
_fornacetta_ (probably the fritting-oven), and let them cool little by
little.’
The next section treats of the preparation of _lattimo bianco_ by
calcining four parts of tin and two parts of lead, and then mixing the
resulting powder with ten parts of Syrian soda. But as is the case with
all the treatises of this class, the majority of the sections are
concerned with the preparation of the various ingredients by means of
which glass may be coloured—the _colori da ismalti_. The green and
opaque red are both obtained from copper-scale, the purple and crimson
from various mixtures of manganese[162] (so spelt in the text), and the
yellow either from iron-scale or from a mixture of resin and tartar. As
for the fine blue—the _zaffiro_—it should be noted that the pigment
employed is described as _azurro da vetro_,[163] probably a preparation
of cobalt—similar to what in later times was known as smalt—which the
glass-workers obtained ready-made from Germany.
In the early sections of the third of these little treatises[164] the
preparation of the soda is described in some detail. Much importance
appears to be attached to the frit, for the third section is headed
‘_Questa si è la pratica di fare la fritta, ciò è li pane del
cristallino. Nota ed impara._’ In the composition of this frit there
enters not only soda and the white pebbles from the Tecino, but a
considerable amount of gromma or tartar, a substance containing potash,
and perhaps lime also.
The preparation of ‘_calcedonio in tutta perfezione_’ is next
described, and I may note that the presence in it of salts of iron and
copper, to say nothing of silver, mercury, and _azurro_, would point to
some variegated mixture resembling the schmelz of later days rather
than to the opalescent glass to which this name was subsequently given
(cf. p. 206).
Of greater importance than any of these little treatises is the work
that Antonio Neri published in 1612. In fact, having regard to the
influence of this book on future writers on the subject, especially
upon those who sought to make glass by Venetian methods in England and
elsewhere, it may without doubt be given the premier place as the most
important work that has ever appeared on the preparation of glass. We
know very little of the author except that he was born in Florence
towards the end of the sixteenth century, that he was a priest, and
that he spent some time at Antwerp, where it would seem that his
attention was first directed towards the manufacture of glass. When,
after the death of the Grand Duke Ferdinand in 1609, the manufacture of
the soft-paste Medici porcelain was abandoned, we are told that in its
place glass-works were established at Pisa, and with these works we may
perhaps connect Neri’s little treatise. I have, however, already gone
over most of the ground covered by this book in my quotations from
Biringuccio and others, and I will postpone the consideration of what
little further is to be gleaned from it until I come, in the account of
our English glass, to speak of the translation of Neri’s book made by
Merret in 1662.