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.
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.