It is after all in the development of the art of blowing glass that the principal merit of the glass-workers, in the age immediately preceding our era, is to be found. By this method the real capabilities of the material, both practical and artistic, were first disclosed. The art was probably first practised on the Phoenician coast, perhaps at Sidon, not long after the time of Alexander. Beside the moulded flasks of which I have spoken above, there are others of plain globular form, with simple short necks, which we may perhaps look upon as among the earliest work of the Phoenician glass-blowers. Some of these are little more than spherical vesicles of the glass as it came from the blowing-tube. With these are associated certain plain spheres of thin glass of various colours, which may have been used as balls by jugglers, as mentioned in a passage in one of Seneca’s letters. But the balls of cool glass, mentioned by other writers, held in their hands by ladies in summer, must surely have been solid, like the spheres of rock crystal put to a similar use by the Japanese. The next step was to give the bulb of glass a ‘kick’ at the base, and to prolong the neck; we have then the type of the so-called lachrymatories, perhaps the commonest and best known form of classical glass.

There is in the British Museum an important collection of blown glass vessels which have been found in Syrian tombs. The actual provenance is here, as indeed in the case of so many other finds of glass, very difficult to ascertain. Some of the pieces are said to come from the neighbourhood of Nazareth, but the majority were probably found nearer to the coast, not far from Sidon and Tyre. The forms are on the whole classical, but Oriental influences may be seen in some cases, as in the double unguentaria which resemble certain Egyptian kohl-pots (Plate VII.). The apparent abundance of this Syrian glass, and the clear, nearly colourless material, point to a time rather after than before our era.

We know that soon after the middle of the first century, all the various forms and applications that we associate with the blown glass of the Romans were in general use in Italy. The proof of this lies in the vast collection of ancient glass in the museum at Naples. There were some years ago in this collection more than eight thousand pieces of glass, and it is constantly being added to. By far the greater part of this glass comes from Pompeii. Now that town was destroyed in the year 79 A.D., and it had sixteen years previously suffered so seriously from an earthquake that little glass can have survived; we are thus able to fix within exceptionally narrow limits the date of most of the glass discovered in the ruins. Apart from a few elaborate examples extracted from the tombs—some of these may well be of an earlier date—we find a vast series of vessels adapted to various domestic purposes, but more especially to uses connected with the storing and drinking of wine. These are for the most part made of a transparent and often colourless blown glass. By this time, then, the art of the glass-blower must have been fully developed in Southern Italy. The Pompeian glass has been well preserved by the thick bed of dry ashes, and has suffered little from surface decomposition.

From a few scattered references in Roman writers we can in a measure trace the rapid change in the position of glass at Rome, say between the latter days of the Republic and the end of the reign of Augustus. Cicero mentions glass as an article of merchandise brought from Egypt, together with paper and linen. Strabo, writing under the rule of Augustus, says that at Rome every day new processes were invented for colouring glass and for simplifying its manufacture, so that ‘a successful imitation of crystal may now be made so cheaply that a drinking-glass with its stand can be sold for a copper coin’ (xvi. 25).

It is not, however, from Italy, or even from Mediterranean lands, that the greater part of the Roman glass in our collections comes, and this is especially the case if we confine ourselves to the ‘hollow ware’—the true blown glass with which we are at present concerned. Already in Pliny’s time the new industry had spread to Spain and Gaul, where, before long, favoured no doubt by the cheapness of the fuel and of the raw materials, important centres of manufacture must have sprung up. We learn from Strabo that not long before his time the Britons obtained what little glass they used—this was confined, indeed, to articles of verroterie—from the Continent. But though we have no direct evidence on this point, there can be little doubt but that glass-works were established at least by the second century in the southern parts of England, and that, to give one example, the large globular and quadrangular urns of greenish glass were made at glass-works not far from the tombs in which they are found.

Indeed, the bulk of this northern glass is of a sepulchral character. The large size and the graceful shapes of the well-known cinerary urns argue a complete mastery of the technical processes, and point to works on an extensive scale where large glass pots must have been in use. These spherical urns owe their preservation for the most part to the fact that they were enclosed in ‘coffins’ of lead or stone. The somewhat prosaic and ungainly square bottles that often replace them must have been blown into a mould of some kind.

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.

I may say at once that the Romans, as far as we know, never attained to any great success in this method of decoration. Its full development was reserved for the Saracens of the thirteenth and fourteenth centuries. This is indeed the one important advance made in the artistic manipulation of glass since ‘the palmy days of Rome.’

Not but that the Romans, and probably to some extent the Phoenicians and the Alexandrian Greeks before them, did not draw and paint upon their glass; but if we may judge from the rare and fragmentary examples that have survived, they were unable to obtain much decorative effect by this means; again, the very poverty and the paint-like quality of such enamels as they used, have doubtless in many cases led to their total disappearance from the surface of the glass.^[36] The painting on the cup-like lids of the little bowls from Cyprus I have already mentioned. On a few fragments of thin glass from Egypt, draped figures have been painted in opaque colours. Perhaps the nearest approach to an effective use of enamel colours may be seen on two little cups found in graves of the fourth century at Varpelev, in Denmark. These Scandinavian tombs have yielded many interesting pieces of glass, as well as some bronze vessels—possibly booty brought home from marauding expeditions. The designs on these cups (they are illustrated in the Proceedings of the Copenhagen Antiquarian Society, 1861) are thus described by Mr. Nesbitt: ‘On the larger one are a lion and a bull, on the lesser two birds with grapes.... The colours are vitrified and slightly in relief—green, blue, and brown may be distinguished.’ (Slade Catalogue, p. xvi. See also some account of glass from these and other Scandinavian tombs in Montelius and Reinach, Les temps prÉhistoriques en SuÈde.)

But the most important and the best preserved example of enamelling on glass is to be found in a small bowl, probably of the third or fourth century, preserved in the treasury of St. Mark at Venice. To this important collection I shall have more than once to return.^[37] The little bowl in question—something over three inches in height—is of a translucent glass of a winy or purplish colour. The seven larger medallions that surround the body are filled with mythological subjects in a fairly good classical style; the pale buff-coloured figures on a black ground imitate an onyx cameo. Each medallion is surrounded by a circle of rosettes of brilliant colours—blue, red, purple, and white. The angular spaces are filled by smaller medallions, each containing a head, and the remaining ground is occupied by a tracery of gold. According to the Canonico Passini, this decoration is in very slight relief, and is executed in what can scarcely be regarded as a true vitrified enamel. The bowl has been mounted at a later time in a light setting of silver gilt with elegant winged handles. But what is more curious, at some time previous to the addition of the mounting, a band of white ornament, resembling cufic letters, but apparently illegible, has been painted round the inside just below the rim, and again outside the base. Much of this later ornament has been abraded, although the original decoration is well preserved, and I think that this fact is an argument in favour of the earlier work being after all of the nature of a true enamel fixed by fire. I describe this bowl here as I cannot see any trace of Byzantine influence in the purely classical medallions.^[38]

Finally, on a few of the gilt catacomb glasses, of which I shall speak shortly, a little coloured enamel is sparingly applied here and there, especially in the draperies.

Engraved and Sculptured Glass

There remains one large division of Roman glass which I have purposely left to the last. In this are comprised the engraved and sculptured pieces, the bulk of which belong to a late time; indeed we may pass from work of this kind to glass that is purely Byzantine in character without any violent transition. But to return for a moment to examples taken from quite the other end of the series, we have seen that the glass bowls that are associated with Alexandrian-Greek and early Roman times are mostly finished by a cutting-tool on some kind of lathe. In the case of the bowl of white glass from Canosa in the British Museum, closely imitating in form the well-known scyphos of the Greek potter, the handles are apparently carved out of a solid mass (cf. p. 46); a very similar bowl in the Charvet collection, said to have come from CumÆ, is illustrated by Froehner. Still more interesting is the large shallow bowl or dish of white glass in our national collection; this is again from a tomb at Canosa. A ring of some twenty spurs, each about half an inch in height, arises from the outer margin; these spurs are carved apparently out of the solid glass. A large rosette cut in low relief, representing a full-blown lotus flower, covers nearly the whole of the surface. With this work we may compare the rosettes, much more rudely carved, it is true, on the base of some very similar bowls of late date from the Rhine country.

Of quite a different character is the carving on those earlier vessels of which we may take the well-known Portland vase as a type. Here the delicate sculpture in low relief takes us back to the cameos of the Hellenistic Greeks, which, as we have seen, were often executed in a glass paste. But few specimens of work of this kind have come down to us—some half-dozen in all—and of these only two are perfect. The body of these vases is formed by two or more superimposed layers of glass, of which the outer one, generally of an opaque white, is ground away by the wheel of the engraver, leaving a design in low relief upon a basis of blue or other colour.

The most famous example of this class is, without doubt, the Barberini or Portland vase, a two-handled urn found towards the end of the sixteenth century in a marble sarcophagus at the Monte del Grano, a lofty tumulus some three miles to the south-east of Rome. Whether the tomb from which the urn was extracted was that of the Emperor Alexander Severus, who was killed in the year 225, is not of much consequence, for the vase itself is certainly of an earlier date. The figures in this case stand out upon a dark blue ground—we need not dwell upon the interpretation of the subject. As Wedgwood long ago pointed out, a rich and almost pictorial effect is given by cutting down the white layer in places nearly, but not quite, to the blue base which then shows through a film of the slightly translucent white paste—an effect, by the way, that is almost lost in the imitations of this vase made in the opaque Wedgwood ware. A curious point about this vase is the fact that the decoration is continued over the circular base on which it stands. This medallion-like space is filled by the bust of a youth with a Phrygian cap wrapped in voluminous drapery. There is some doubt, however, whether this medallion is of so early a date as the rest of the vase.^[39]

Almost identical with the Portland vase in technique and material is the amphora of onyx glass, carved as a cameo in low relief, which was found in 1837 in a tomb on the Strada dei Sepolcri at Pompeii. In this case we have a limit—a terminus ad quem—for the date, the middle, that is to say, of the first century of our era. But the work may well be of a somewhat earlier time than this. The decoration is distinctly Alexandrian in character. Notice especially the band at the lower part with the sheep feeding under trees—in this we are at once carried back to the pastoral poetry of Sicily. It will be observed that the vintage scenes with the little naked ‘putti’ are placed under the handles, while the place of honour is reserved for the beautiful design of vine-branches, masks, and birds. The highly developed technical skill required, especially in the preliminary blowing and ‘casing’ of the glass, is, however, an argument against throwing back too far the date of vases of this class.

Some fragments of another vase of a similar character were found at Pompeii at a later date; the pieces after passing through various hands are now in the British Museum, where they have been united to form (with extensive gaps) an oenochoË or jug, known as the Auldjo vase, from the former owner of most of the fragments; in this case the decoration of the parts preserved consists chiefly of vine and ivy leaves. There are at Naples many fragments of onyx glass equal in beauty and skill of execution to these well-known vases. Among these, the half of a patera decorated, on a dark blue ground, with a mask surrounded by the leaves of the Oriental plane, is of exceptional merit. In other cases the parts in relief seem to have been cast separately and fixed on to the surface, a technical process of quite another nature.

In all these examples the work of the artist follows closely on the lines of the carver of cameos—especially of those cameos where advantage is taken of the parallel layers of the natural stone, as in the case of the sardonyx and of the niccolo; it is for this reason that I have described the material of our Barberini and similar vases as onyx glass. But there was another and purer variety of quartz that was coming more and more into favour during the third and fourth centuries. From this time onward all through the early Middle Ages, if we are to judge from the treasures preserved in Christian churches, to nothing was more value attached than to vases and cups of rock crystal, often of imposing dimensions, carved in shallow or deep relief. When once the process of making a clear colourless glass was mastered, this natural crystal could be very closely imitated in a material which was more easily worked. The carvings on the great majority of the examples of rock crystal that have come down to us—for example, the vases in the Louvre from the Abbey of St. Denis, and those still preserved in the treasury of St. Mark’s—are of a distinctly Byzantine, if not rather of a Sassanian or even Saracenic character, and this style is reflected upon much of the ‘crystal’ glass which is so often confused with the harder stone.^[40]

The Romans of the fourth century were great masters of the art of cutting hard stones. Along with a general decline in taste and artistic invention, there was some advance in the direction of what we should now call applied science, and this is exemplified in the nature of the ‘metal’ and in the method of carving of the later Roman glass.

In the case of this later engraved glass, the lapidary’s wheel was applied at times to produce a rough design by a series of burr-like marks, or again the pattern was built up of a number of shallow, mostly oval depressions; in other examples the glass was deeply undercut, so that the designs appear to float round the vessel, to which indeed they are only attached by small rods not easily visible. Of the last kind is the work that may conveniently be called diatretum, although it is by no means certain that the diatretarii, mentioned by Ulpian and others, were necessarily workers in glass, seeing that carvings of this description, whether in metal, in hard stones, or in our material, were equally in favour at this time.

We have, unfortunately, no complete example of this undercut work easily accessible in our public collections. A fragment, however, in the British Museum throws much light upon the process of manufacture. On this piece there remains a portion of the outer frame in the form of a few letters that have formed part of an inscription; most of these letters, however, have been broken away, and we are thus enabled to see the base of the rods that supported them. The sharp angles of these little rods, and the marks on the surface of the glass, point unmistakably to the use of a cutting-tool, nor is there, I think, any trace of soldering at the base of the rods. We must turn again to the marvellous collection of late classical and mediÆval objects that has been so long preserved in the treasury of St. Mark’s at Venice for the most complete specimen of this undercut glass. Here will be found a situla, or bucket-shaped vessel, of slightly greenish glass, about eleven inches in height (Plate XIV.). On the upper zone is a hunting scene with two horsemen, treated with a certain energy that calls to mind some of the Byzantine and even Sassanian work of the fourth and fifth centuries. Below we have a raised network, or rather grating—for the motive seems to be taken from a grille of iron or bronze—formed of four rows, each built up of fifteen tangential circles bound together at the points of contact. About half of these circles are more or less broken, and neither on the ground nor on the supporting rods thus disclosed was I able on close examination to discover any of those marks of a cutting-tool so prominent on the British Museum fragment. Indeed it is very possible that this late example may be built up of separately cast pieces soldered on to the base.

The famous cup of diatretum glass found near Strassburg was destroyed during the bombardment of that city in 1870; it bore an imperfect inscription in raised letters, which has been interpreted as referring to the Emperor Maximianus Herculius, the partner of Constantine in the empire, who put an end to his life in 310. In this case a network of red glass and an inscription of green glass were superimposed upon a nearly colourless ground. So in another cup preserved in the Palazzo Trivulzio at Milan, the inscription Bibe Vivas Multos Annos is again in green glass, but the network is here blue. Where the detached decoration is of a different colour from the base, the original vase must have been of an onyx glass formed by a ‘casing’ process and of considerable thickness, unless, indeed, we are to regard the lettering and the network in such cases as formed separately and attached to the base by the little rods. Perhaps the finest example of a vas diatretum is the bowl found in a stone sarcophagus at Worms, of which the fragments are now divided between the museums of Bonn and Mainz. In the former museum may also be seen a tall amphora-shaped vase (some twenty inches in height), with Bacchic scenes carved in low relief, which was found in the same coffin.

The oviform bowl belonging to Lord Rothschild is carved in an olive-green glass, which appears of a deep red by transmitted light. It is surrounded by five figures in what is practically complete relief; the subject represented appears to be the ‘Madness of Lycurgus.’ The arms and the draperies of these figures are connected to the base by little rods as in the previous examples, but to judge from certain cavities in the interior corresponding to the principal external bossages, the glass was originally cast in a mould.^[41]

The often-quoted expression of Martial, ‘SurrentinÆ leve toreumata rotÆ,’ written before the end of the first century, can hardly refer to this undercut work, which seems to be all of a much later date, nor is it even certain that the words refer to objects carved in glass rather than in rock crystal and agate. The word toreumata is used in connection with silver and even of earthenware. So the calices and toreumata Nili of the same writer (xi. 12) seem from the context to be rather carved in some precious stone. The following lines, however, are headed ‘Calices Vitrei’:

In some other references to glass in Martial’s Epigrams it is mentioned as a cheap material, and contrasted with gold or rock crystal.

As a rule, however, this late Roman glass was cut in very low relief. The design was often given by the juxtaposition of a number of ovoid depressions and furrows scooped in a perfunctory fashion by means of a lapidary’s wheel of some size.^[42] At times this wheel was applied so as to make a rough burr on the surface; on the other hand but little use was made of the simple engraved line that we find on the German glass of the seventeenth century.

The designs on this later engraved glass are almost without exception of the most wretched description; any interest they may have is archÆological, and dependent upon the subject treated. Many pieces, especially in the form of shallow bowls, have been found in tombs of the third and fourth centuries in the Rhine district, especially around Cologne. Some of these bear inscriptions in often very faulty Greek, but I do not think that this is a reason for inferring that they are not of local manufacture.^[43] On one cup from Cologne the creation of man by Prometheus is represented, but the majority of the subjects are of a more or less Bacchanalian or even of an erotic character. It has been attempted to connect these with the tabernÆ, the roadside inns—places of no good repute in those days—and even to find representations of these hostelries in certain tall and evidently secular buildings engraved on them.

Still more curious are the spherical ampullÆ on which a panoramic landscape is roughly scratched; in every case the scene represented is the coast-line from the bay of BaiÆ to Pozzuoli, the names of the various temples and palaces being indicated by inscriptions. (See Froehner, p. 96.)

Most of this engraved glass dates from a time when Christianity was widely diffused, but we rarely find on it subjects connected with the new religion. It would seem that the associations connected with the glass thus decorated were not such as would recommend it for Christian use. The early fathers protested against all such elaborate and vain arts. ‘The pretentious and useless vainglory of the engravers on vessels of glass may well cause those who use them to tremble, and such work should be exterminated by our good institutions,’—so wrote Clement of Alexandria early in the third century (quoted by M. Gerspach, p. 49). There is little to say from the artistic side for the few specimens of engraved Christian glass that have come down to us; their aim is purely didactic and for edification.

The wheel was sometimes employed by the Romans to form a simple pattern by means of a series of polished ovoid depressions; when these are placed close together, the effect somewhat resembles that of our modern facetted glass. The resemblance is still more close when the surface is cut with a series of intersecting diagonal furrows, as on the spherical bottle at South Kensington, illustrated by Mr. Nesbitt in his catalogue.

I have now run through the principal varieties of Roman glass, and the order in which I have arranged the different classes—the inlaid and millefiori first, then the moulded, the blown, and finally, the cut and engraved glass—is in a measure a chronological one, following roughly the order in which these various methods of working and styles of decoration succeeded one another, or rather were dominant, in successive ages. I will end this chapter with a few notes concerning the methods of preparation and the geographical distribution of Roman glass.

As far as contemporary evidence goes, all our information on the first head is derived from the brief and very unsatisfactory statements of Pliny. There is, however, every reason to believe that there were few important changes in the construction of the furnaces, or in the preparation of the materials, during the time that intervened between, say, the fourth century of our era and the period in the Middle Ages with regard to which we have further sources of information. That is to say, we may regard the comparatively adequate account of the manufacture of glass given by the monk Theophilus, and by the pseudo-Heraclius,^[44] as on the whole applicable to Roman times. Even at the present day at Murano, and doubtless at other glass-works little affected by modern industrial processes, much of the old method of working and many of the old terms remain almost unchanged. To give but one example:—when the workman is preparing the half-liquid gathering or ball of glass at the end of his blowing-tube, previous to inflating it with his breath to form the paraison or vesicle, he trundles the viscous mass upon a slab of iron which rests on the ground beside his furnace. This iron slab is known as the ‘marver’—there are similar names for it in other European languages—and it is always understood that the plate in question was formerly made of marble. So, no doubt, it may have been at some remote period, but we find that the pseudo-Heraclius, describing in the twelfth century or thereabouts the manufacture of glass, speaks of this same plate as ‘tabula ferri quÆ marmor vocatur.’ Perhaps we should have to go back to the stone slab on which the Egyptian glass was rolled to find the origin of this ‘marver.’^[45]

We must now see what can be made out of the somewhat rambling account of the origin and manufacture of glass given by Pliny at the end of his thirty-sixth book (cap. 44-47). Pliny regarded glass as a Syrian invention. For many centuries, he tells us, the sole source of the principal constituent was a small tract of sand thrown up by the sea at a spot on the Phoenician coast near the town of Ptolemais, where the river Belus^[46] flows into the Mediterranean. With this sand the natives mixed the nitrum, imported oversea in cakes,^[47] and thereby for the first time formed glass. According to Pliny, these Phoenicians were astute and ingenious craftsmen, and they, in time, took to adding to their glass-pots the ‘magnes lapis, which, it is asserted, draws to it the melted glass like iron.’ This is a statement most characteristic of Pliny. The magnes lapis—magnetic iron-ore or loadstone—is the last substance in the world any one would think of adding to glass. But we know that the ancients knew of two kinds of black stone, for one of which they used the masculine form magnes—this was the loadstone—for the other the female form magnesia;^[48] and this magnesia, at any rate at a somewhat later period, can be undoubtedly identified with the black oxide of manganese (MnO₂), a substance known of old as the ‘soap of glass,’ from its power of removing the green colour derived from iron. Now we have seen that pure white glass, ‘cleansed’ probably by this method, had only comparatively lately been introduced into Italy, and some confused account of the new discovery had probably reached Pliny’s ears. ‘In the same way,’ he continues, ‘they took to adding to the fused mass shining pebbles, then shells and sandy concretions (fossiles arenÆ).’ In these ‘fossils’ we may, perhaps, recognise the source from which was obtained the lime, an essential constituent of glass. Passing over some obscure references to the nitre of Ophir and the copper of Cyprus, Pliny goes on to say that the whole is melted ‘like bronze,’ in closely grouped furnaces, and that a blackish mass of fatty aspect is obtained. This we must regard as a preliminary frit, for we are told that the mass is melted again in the glass-house, where the requisite colouring matter is added to it. ‘So the work was carried on of old in the famous glass-works of Sidon.... At times the glass was shaped by blowing, or again it was abraded by the wheel, or carved in the manner of silver.... Such was the ancient way of making glass. At the present day in Italy also, by the mouth of the river Vulturnus, for a space of six miles between CumÆ and Liternum, a white and most soft sand is collected, which is pounded both in mortar and mill; it is then mixed with three parts of nitrum,^[49] by weight or by measure, and after melting is transferred to other furnaces. In these the substance, now known as ammonitrum, is melted and then cast into cakes. These cakes are again fused to obtain pure glass and cakes of white glass.’

Pliny, in this confused account, where we have apparently materials from different sources imperfectly welded together, appears to contrast an older method of manufacture, practised formerly at Sidon, whose glass-works he seems to refer to as things of the past, with the newer processes now in use in Italy. It will be noted that in both cases a preliminary frit was prepared, although the term ammonitrum, a word of Greek origin, is applied to this frit in the latter case only.

‘Already,’ says Pliny, ‘the new art of melting sand with soda (literally “of tempering sand”) has spread through Gaul and Spain.’ He then goes on to tell, but with an expression of incredulity quite unusual with him, the story of the discovery of a malleable glass. According to this tale (in its earliest form), Tiberius ordered the workshop of the man who so tempered glass that it became flexible, to be pulled down, lest the value of bronze, silver, and gold should be depreciated. This story was the delight of the renaissance writers on glass. With regard to the more amplified and tragic version usually quoted from Petronius, we must remember that the remarks put by that writer into the mouth of Trimalchio are not always to be taken seriously. In later days a similar tale was told of a French inventor—in this Richelieu takes the place of Tiberius. After mentioning the calices pteroti, the costly ‘winged cups’ of Nero, Pliny gives some account (quite out of its proper place, by the way) of obsidian, a black stone much resembling glass, which was shaped not only into various dishes for use at the table, but also into figures of some size—statues of the divine Augustus, for instance, for that monarch much prized the material. Vitrum hÆmatinum, ‘a red opaque glass,’ is passed over rapidly. ‘White glass is made also, and murrhine and glass resembling the hyacinth and the sapphire and glass of all other colours.^[50] There is no substance easier to work or to which brighter colours can be given. The highest place must, however, be accorded to the white transparent glass which much resembles crystal; for drinking, it has driven out vessels of gold and silver.’ This passage is of the greatest importance. We see that a pure white glass was still, even in Pliny’s time, something noticeable. This was, as we shall see, again the case at the time of the Renaissance, when it was the aim of the glass-makers, all over Western Europe, to imitate the Vetro di cristallo of the Venetians.

It will be noticed that Pliny makes no mention of the method of preparation of the alkali used in making glass (in ‘tempering the sand,’ as he puts it). From the context it would seem that the nitrum was always of the same nature as that brought by the mariners to the Phoenician coast—this is, however, very unlikely. Nor have we any information about the arrangement of the furnaces. These glass houses were, however, well known to the beggars and loungers of the time—we hear of them as places of resort in cold weather for those who had no other way of warming themselves. In the Greek Anthology (No. 323), of all places in the world, there is a fragment by one Mesomedes, a contemporary and favourite of Hadrian, giving an account of a visit to a glass-house. Just at the point where the little poem breaks off, the workman is described as placing the molten mass between the blades of the pincers or shears.

Strabo tells us that when he was at Alexandria—he was there, we know, in the early part of the reign of Augustus (circa 24 B.C.)—he was assured by the glass-workers (?a???????) that their ‘many-coloured and sumptuous glass’ could not be made without the addition of a certain glassy earth which was only found in Egypt, a story which points to the jealousy of foreign competition on the part of these craftsmen. So on the Phoenician coast he hears from some of the wonderful qualities of the Sidonian sand, while others tell him that one sand is as good as another. Strabo goes on to speak of the improvements made ‘quite lately’ in the clear crystal glass of which the manufacture had not long since been established at Rome. Compare with this the account of Pliny; in view of his certainly rather vague statements, we should hardly have looked for this cristallo in Italy at so early a date.

But it is neither from Italy nor from the countries bordering the Eastern Mediterranean that the most important supply of Roman glass has been obtained. Putting aside objects of quite local provenance, it will be found that in the museums of England, France, and Germany, by far the larger part of the glass exhibited—and this is above all the case with the blown glass—has been found within the limits of the ancient Gallia. Spain, contrary to what we might have expected, has yielded little Roman glass of any artistic merit, partly perhaps for want of systematic search. But there are few districts in France or in the west of Germany where the exploration of Roman cemeteries has not yielded a plentiful crop. If we travel northward from the estuary of the Rhone by way of Arles and Nismes to Avignon, Valence, and Lyons, then across by the country on either side of the Jura to the valley of the Rhine, and follow that river by Strassburg to Cologne, we pass for the whole way through a district especially rich in Roman glass. And this is what might well be looked for. The third and fourth centuries—a little earlier or a little later, according to locality—are above all the great centuries for the prevalent use of glass, and it was during this period that the central tract of country that included the two great metropolitan cities of Arles and TrÈves began to take the prominent place that it maintained throughout the early Middle Ages.

Even our English glass of this time, so much of which comes from districts to the north and the south of the estuary of the Thames, may be brought commercially at least into connection with the wealthy provinces of Northern and Eastern Gaul. It was from these provinces that glass was first imported, and from them, no doubt, the glass-workers passed over to Britain.

In the case of the rich collection of Roman glass in the British Museum, the backbone, as it were, is formed by the specimens excavated from tombs in the neighbourhood of the lower Rhone valley—from Vaison, near Vaucluse (the Comarmond collection), from Apt, and from Alais. At Arles, in that district of tombs, the Aliscamps, which furnished Dante with a well-known image, beneath the Christian sarcophagi (in these, too, not a little glass has been found), the earlier Roman tombs lie on the bed-rock. From these tombs numberless urns of glass, in cases of lead or stone, have been taken, as well as many examples of glass of rare and exceptional shapes—among others what is apparently an alembic for use in distillation. Some of these vessels contain a red liquid which may represent at least the wine with which they were originally filled (Froehner, p. 109). In this town of Arles, too, in the suburb of Trinquetailles, there were probably extensive glass-works, as we may infer from the quantity of vitrified paste there found (Quicherat, Revue ArchÉologique, xxviii.).

To pass to the Roman cemeteries of Lyons: in the museum of that town are some curious masses of blue frit taken lately from a tomb on the FourviÈre, which call to mind the fritted cobalt or smalt exported in modern times from the Saxon mines. We have in the British Museum many pieces of glass from older explorations at the adjacent suburb of St. IrÉnÉe. There is in the Lyons Museum a sepulchral stele of much interest found in this very district; it is to the memory of a certain Julius Alexander, a citizen of Carthage, a craftsman in the art of glass (opifici artis vitreÆ). This Punic glass-blower left behind him children and grandchildren, who doubtless followed his trade. We must not infer too much from a single instance; we know, however, from other sources,^[51] that there was a large influx into Gaul at this time of Semitic people, chiefly of a humble status, craftsmen and small merchants, and that they found their way in above all by the valley of the Rhone. These ubiquitous traders are generally referred to as Syrians, and I think it likely that the glass trade, not only in the south of Gaul but further afield, may have been in great measure in the hands of Orientals of this class. This would be especially true of the manufacture and hawking about of small objects of verroterie,^[52] and again of glass pastes containing lead. But perhaps also the preparation of the more ambitious and artistic kinds of glass was in the same hands, leaving only the common ware to the native workmen; in that case the distinction so important in later days between the cristallo and the ‘forest-glass’ may have had its prototype in Roman times. It should be borne in mind that these Semitic craftsmen would for the most part speak Greek rather than Latin, an important point that I have not space to develop here.

As we pass to Northern Gaul we find examples of a glass of a pronounced greenish tint more and more predominating—bulky urns, square and spherical, and jugs with ‘claw’ handles. All of these forms we are familiar with in England. The museums of Amiens and Boulogne are especially rich in this glass, and in Paris the local finds are well represented in the MusÉe Carnavalet.

On the other hand, in the glass of the Rhine district, including of course the Moselle, we have a return to the more varied types that we met with in the south. TrÈves was the northern rival of Arles; it formed the centre of a rich district, including Lorraine on the one hand and the Rhine provinces on the other, where the manufacture of glass by the third century became an important industry. And this district has for us a special interest, for here more than anywhere else we have some evidence to show that the industry was carried on without interruption throughout the Middle Ages. The museums of TrÈves, of Cologne and of Bonn, are above all rich in Roman glass, and the German archÆologists have endeavoured—and this has hardly been attempted elsewhere—to arrange this glass in a chronological sequence. They think that they can distinguish the following stages in the industry:—1. Up to 50 A.D. glass was a rarity in the north, but the millefiori and marbled glass of the south was imported to some extent. 2. After the middle of the first century, glass-works were established for the manufacture of large urns and smaller vessels of a ‘Natur-glas,’ bluish rather than greenish in tint. 3. In the time of Hadrian (117-130 A.D.) a pure white glass was introduced; this was more liable to decay than the older bluish glass. 4. The period of the greatest development was about 200 A.D. Many kinds of decoration were in fashion, as zig-zag threadings on coloured glass. 5. After 250 A.D. This was the time of the glass with the Frontinus stamp.^[53] The prevailing tint is a strong green, no longer bluish; the decoration is given chiefly by engraving and cutting; Christian subjects begin to appear. To this period also belongs glass decorated with coloured medallions of glass paste.

I give this scheme of classification under all reserve; the interlarding of a period of white glass between two stages of ‘green glass’ may perhaps be open to criticism, but at all events it is a step in the right direction. It must be borne in mind that this Rhenish glass belongs to the same Romano-Celtic family as that found in France, but, as in the latter country, the Celtic element is scarcely perceptible. The art was an entirely new one, and there was no earlier tradition to influence the work as in the case of the contemporary pottery, armour, or sculpture.

It so happens that the Roman glass of Gaul has been most carefully studied in a district far away from the route that we have been following. In Western France the researches of M. Benjamin Fillon (L’Art de la terre chez les Poitevins, 1864, and other works) have brought to light the remains of old glass-works. These appear to have been generally situated far from the main centres, and they were often associated with potteries. It would even seem that glass was at one time more in favour and perhaps cheaper than earthenware. A curious point is the number of localities in Poitou and La VendÉe which bear names such as La Verrerie and VerriÈre; at as many as seven places with names of this class, M. Fillon claims to have found the remains of Gallo-Roman glass-works. These do not appear to have been established before the time of Trajan, and it is to the age of the Antonines in the second century that the more important examples of glass are to be attributed. Of somewhat later date than this, however, are the fifty pieces of white glass from the villa and tomb of a femme-artiste at St. MÉdard-des-PrÉs. This was M. Fillon’s most important find; some of the vases contained various coloured substances and resins, and they were closed by stoppers of wood or by sheaths of bronze.^[54]

The British Museum has lately acquired a large collection of Gallo-Roman glass formed by M. Moret. Among this glass—it comes chiefly from late Gallic cemeteries in the neighbourhood of Paris, as from Corbeil and Conflans (Confluentia), and also from the Rheims district—may be seen beakers with circular feet and wide-mouthed cups with rounded bases.^[55] To one of these a fantastic decoration has been given by a contorted streak of blood-like tint in the midst of the glass—caused by the perhaps accidental presence of a fragment of copper-oxide; we have here at any rate one of the earliest instances of the use of this valuable pigment to obtain a transparent red. Notice, too, the large receptacle cast in the form of a fish; similar vessels have been found at Arles, and they have been brought into connection with the well-known Christian symbol of the ?????.

Roman Glass in Britain

There does not seem to be any example of a vessel of glass from a pre-Roman tomb in Britain. The little ribbed bowls that have been found in Celtic tombs further south did not apparently reach our country. The ?a?a s?e?? and the ????????a mentioned by Strabo in an involved passage as among the imports into Britain, we must interpret as beads of glass and amber. From that time until the eighth century, when the Venerable Bede wrote his history, we have not a word of documentary evidence bearing upon the question of glass in our country. Nor have we any definite evidence, apart from a few lumps of glass that may have had their origin in an accidental fire, that any glass-works existed in England during this long interval,—no evidence, that is to say, apart from that based upon the large amount of Roman glass found in England and the size of many of the specimens. The English glass, however, in no way differs from that taken from Roman tombs in the north of France. I have mentioned already the most noticeable types—the large urns, both spherical and quadrangular, the graceful jugs and vases with ribbed handles, and the little bowls of thin moulded glass with scenes taken from the circus. It is perhaps remarkable that the art of the enameller on metal, which we know at this time had been brought to a great perfection in Britain,^[56] appears in no way to have influenced the glass-blower, and it would seem that in Britain glass vessels have been rarely found together with specimens of champlevÉ enamel.^[57]

Most of the finer examples of native Roman glass in our museums have been excavated from cemeteries adjacent to the lower Thames valley, around Colchester and other stations to the north, but above all on the southern bank, in the district lying between the mouth of the Medway and the Isle of Thanet. In this neighbourhood, in the flat land between Sittingbourne and Faversham, were situated what were probably the most extensive potteries of Britain, and it is hereabouts if anywhere in England that we might look for traces of glass-works of Roman date. As we go further west and further north, glass, large examples at any rate, becomes comparatively rare, and this is true even of the neighbourhood of such important stations as York and Cirencester.

PLATE IX

ROMAN GLASS FROM BRITISH GRAVES