Little or no trace of local influence can be found in the shapes or the material of the glass made in the second, third, and fourth centuries in Gaul, in Britain, or on the Rhine. In the Glass-Room in the British Museum, the large vessels of blown glass are chiefly of Gallic origin; the most important come from a collection made many years ago in the south-east of France. They may be compared with the Roman glass found in Britain exhibited in the Central Saloon. On the whole, these large glass urns are characteristic of the northern and western provinces. While they appear to be unknown in Greece and in the East, in the Roman columbaria they form a very small proportion of the urns ranged in the niches and along the shelves.

The gigantic cinerary urns from Kentish cemeteries are only rivalled in size by some of the Pompeian glass at Naples. Among the glass from cemeteries in Southern Britain in the British Museum are many jugs and bottles of quaint and original form, and others which for grace and purity of outline it would be difficult to rival elsewhere ([Plate IX.]). Notice especially the handles, and above all the insertion of the lower end of these handles into the side of the vessel. It is the neglect of attention to this point that so often gives an impression of weakness to the handles of modern ware, whether of pottery or of glass. But here the ribbed handle terminates in spreading lines that clasp the flank of the jug like the claws of a bird of prey; I do not know of any happier or simpler application of the viscous material. At times the central rib of the handle is prolonged into a wing-like flange descending nearly to the base of the vase, or may be ending in a long trail of glass worked by the pucella into quills or teeth.

A greater variety of forms is naturally found in glass made for domestic use than in specimens destined for the tomb. It is this variety that gives a special interest to the collection at Naples. M. Froehner has described nearly thirty different forms of glass vessels (Collection Charvet, pp. 76-80), and has attempted to apply to each of them the distinctive classical name, both Greek and Latin. But many of these terms are rather names of Greek fictile ware than of Roman glass, and as to the remainder, it is rather to the Byzantine scholiasts of later times than to writers of a good period, where allusions to glass are rare and vague, that resource has been had. The richest mines for information of this kind are the works of Petronius and Athenæus—this last author gives a list of a hundred varieties of drinking-vessels. But in both cases it is of vessels of silver or of pottery rather than of glass that the writer is generally thinking.

As a rule, the shapes and methods of decoration of Roman glass follow a line of their own, dependent on the ‘habits’ of the material. It is, however, easy to recognise forms derived from pottery, and even from bronze, in any large collection of Roman glass. Just as the so-called Samian ware is imitated in the moulded glass bowls, so we find that a class of pottery, common in England, in which the soft clay has been pressed in, perhaps with the fingers, to form on the sides vertical trough-like depressions, has been closely imitated in blown glass—such rounded depressions are easily given to the paraison by means of a blunt piece of wood. Again, the decoration of white slip, equally common on Romano-British fictile ware, is imitated by means of ‘trailed stringings’ on glass, if indeed in this case the imitation is not in some measure the other way—from glass to pottery.

Perhaps the most characteristic decoration of the earlier transparent glass is given by a series of parallel ribs. This ‘pillar moulding’ may be formed on the surface in various ways—by stringings partly melted on to the surface, or by the use of a mould at one period in the development of the paraison. A graceful type of these little ribbed or gadrooned bowls—amber coloured, or again white with blue ribs—has been found over and over again in pre-Roman tombs on both sides of the Alps; these bowls are often seen in the museums of Switzerland and North Italy. Apart from beads and small objects of verroterie, they appear to be the earliest articles of glass exported to the Celtic tribes of these districts, but nothing is known as to their place of origin. In other cases such ribs or stringings, bending round the body in a more or less gentle spiral, form a very happy scheme of ornament.

The decoration by trailed stringings—necessarily a rapid process, by which happy effects are sometimes attained almost by accident—may be regarded as a genuinely vitreous process. It is often combined with fringes and toothings impressed—on the margin of the handles above all—by the rapid and skilful use of the pincers. The commonest, and probably the oldest, application is as a more or less closely coiled stringing round the neck of the bottle or jug; this is convenient for handling, and gives the appearance at least of additional strength. The stringings on the later forms tend to hang loose upon the surface, sometimes taking the form of hastily written characters.[[34]]

The cords and threadings may often be of a different colour from the vessel upon which they are applied—they may be reduced to knots or mere drops applied here and there. In such cases we have an apparent approach to decoration by enamel. But the form of ornament that we are now dealing with is applied directly to the soft paraison or to the still unfinished vessel, and the glass of which the stringings are formed is probably of the same composition as that on which it is superimposed.

So of the splashed or mottled ware. We have here real splashes of a liquid material applied to the paraison while still on the blowing-tube. When the neck was subsequently shaped, these circular markings were drawn out into ellipsoid forms, showing that this part of the vessel was made at a later period. It is instructive to compare this result of the work of the blowing-tube with the patterns on the millefiori bowls. In these latter patterns we find no trace of subsequent distortion—a proof that the glass of which they form part has never passed through the stage of a paraison or vesicle.[[35]]

Enamelling on Glass

I now for the first time have to treat of the decoration of glass by enamel painting. It may be as well here to explain that in a true enamel, as the term is used in ceramic and vitreous art, the coloured decoration is applied to the glassy surface (either glaze or glass body) in the form of a pigment worked up with water or other liquid. Such enamel paints are composed, in later times at least, of a base of silicate of lead (the flux), coloured by various metallic oxides. It is essential that these enamels should be more fusible than the body on which they are painted, so that when subjected to the heat of the muffle-fire they may be completely fused, while the glass or glaze on which they rest is not more than superficially softened. Such enamel decoration, whether on porcelain or on glass, may vary from a mere wash of colour on the one hand, of which it is sometimes difficult to say whether it has ever been subjected to the heat of the muffle-fire, to a true vitreous covering on the other, where the various colours stand out in relief like so many jewels.