Glass manufacture at Akhetaten
from Tell el Amarna by W. M. F. Petrie

Chapter IV

The Manufactures

51. The new capital of Akhenaten needed a large amount of decorative work, and suitable factories sprung up to supply the material. The glazes and glass were the two principal manufactures, and in those lines under the impulse of the new art a variety and a brilliancy was attained, which was never reached in earlier or later times. So far as the use of glazes is possible, this period shews the highest degree of success, and the greatest variety of application.
Fortunately the sites of three or four glass factories, and two large glazing works, were discovered ; and though the actual work-rooms had almost vanished, the waste heaps v/ere full of fragments which shewed the methods employed : moreover the waste heaps of the palace, as we have mentioned in Chap. II, contained hundreds of pieces of glass vases which illustrate the finished objects.
We can therefore now trace almost every stage and detail of the mode of manufacture; and in this chapter we shall follow the course of the processes employed for both glass and glazes.

52. We are already familiar with the frits made by the Egyptians, from the Xllth dynasty onward, for colouring purposes. These have been carefully analyzed and remade by Dr. Russell; and we know that the components were silica, lime, alkaline carbonates, and copper carbonate varying from 3 per cent, in delicate greenish blue, up to 20 per cent, in rich purple blue (see " Medum," p. 44). The green tints are always produced if iron be present; and it is difficult, if not impossible, to obtain silica from sand without the iron in it preventing the blues being produced.
One of the first requisites therefore is to obtain the elements of the mixture free from iron. How this could be done was quite unknown until I picked up a piece of a pan of frit, which had been broken in the furnace and rejected, before it was combined. This shewed clearly throughout the mass the chips of white silica; and from their forms they were clearly the result of crushing the quartz pebbles which are to be found on the surface of the desert, having been rolled down by the Nile from the disintegration of primitive rocks further south. The half-formed frit was of a fine violet colour, proving the freedom of it from iron. The lime, alkali, and copper had combined already, and the silica was in course of solution and combination with the alkali and lime, half dissolved like sugar stirred into a pudding. The carbonic acid in the lime and alkali had been partly liberated by the dissolved silica, and had raised the mass into a spongy paste. With longer continued heating the silica in ordinary samples has entirely disappeared, and formed a mixture of more or less fusible silicates. These made a pasty mass, when kept at the temperature required to produce the fine colours; and this mass was then moulded into pats, and toasted in the furnace until the desired tint was reached by the requisite time and heat; and a soft crystalline, porous, friable cake of colour was produced.

53. Among the furnace-waste were many pebbles of white quartz. These had been laid as a cobble floor in the furnace, and served as a clean space on which to toast the pats of colour, for scraps of the paste of frit were found sticking to one side of the pebbles. This floor also served to lay objects on for glazing, as the superfluous glaze had run down and spread over the pebbles as a thin wash of green. Doubtless this use of the pebbles was two-fold; they provided a clean furnace floor, and they became disintegrated by the repeated heating so that they were the more readily crushed for mixture in the frits afterwards.
The half-pan of uncombined frit shews exactly the size and form of the fritting-pans, about lO inches across and 3 inches deep. Among the furnace-waste were also many pieces of cylindrical jars, about 7 inches across and 5 inches high. These jars almost always had glaze run down the outside of them, from the closed end to the open end; the glaze is of various colours, blue, green, white, black, etc., evidently leaked from the pans of glass. Hence they must have stood mouth downward in the furnace, to support the fritting-pans and glass crucibles above the fire, as shewn below (Pic. 62).

Fritting pans, supported in the furnace on jars, inverted, down which the glass runs.

54. Of the furnaces used for glass-making we have no example; but a furnace that was found near the great mould and glaze factory was apparently used for charcoal-burning, as a great quantity of charcoal was found in it, but no trace of pans, jars, or glass. This furnace (see picture on the right) was an irregular square varying from 43 to 57 inches at the sides. It was originally about 35 inches high, but the roof was destroyed. The northern door was 29 high and 15 wide, to admit the north wind, and to serve for tending the furnace on the windward side. While the south or exit door was 16 high and 13 wide, for the gases to pass off. Probably the glazing furnaces were on the same principle; and perhaps even the same furnace would be used for varying purposes.

55. Of the stages of production of the glass we have a continuous series. The crucibles in which it was melted were deeper than the fritting-pans; being about two or three inches in depth and diameter. The form is shewn by the outlines of the pieces of glass, and most fully by piece 40, picture on the left, which gives a section of the vessel in which it cooled. Many such pieces of glass are found retaining the rough surface, and even chips of the crucible adhering to them; while the old top surface shews the smooth melted face, with edges drawn up by capillary attraction. The upper part is often frothy and worthless. This proves that the materials were fused in these vessels, as the froth of carbonic acid expelled by combination was yet in the vessel. If the glass had been made eleswhere and then merely remelted here it would have been clear. Moreover, by the manner in which the crucible has in all cases been chipped off the lump of glass after cooling, it is certain that the glass was left to cool in the crucible; so as to gradually let the scum rise, and the sediment sink, as is now done with optical glass. If the glass had been poured out, we should not have found such pieces as these; on the contrary we ought then to have found masses of cast glass, which have never yet been discovered. It is therefore plain that the glass after melting was left to stand in the crucibles until the furnace was cool; the blocks were then removed, the crucibles chipped away, the defective parts of the glass—scum and sediment—were chipped off, and a clear lump of good glass was thus obtained for working up.
While the glass was being made samples were taken out by means of a pair of pincers, to test the colour and quality; and many of these samplings (as 41, 42 in the drawing on the right) were found, shewing the impress of the round-tipped pincers.

56. After obtaining the lumps of clear glass these were broken up into suitable sizes, and heated to softness. They were then laid on a flat surface, and rolled by a bar worked diagonally across them. This method prevents flattening in the roll, which is liable to occur in a pasty material if rolled at right angles to the length. Also a rolled paste is liable (like hammered iron rods) to become hollow in the middle owing to over expansion of the outside, and so to crack up lengthways. But by pressing only a short length at once in rolling, by a diagonal bar, the rest of the material holds it together and tends to prevent splitting. Again, by rolling only a small area at once, much greater pressure can be applied, and hence the glass could be rolled cooler, and without such risk of flattening. The marks of the diagonal rolling are seen on the finished rolls, as in the drawing on the right, No. 43.
The next stages, after thus obtaining thick rods of glass, were to draw this out, as in producing what is now known as "cane"; or to flatten it into strips, which were polished and used for inlaying, or else drawn out like the rods, thus forming thin glass ribbon. A third variety of drawn glass are the tubes, drawing on the right 51, 52. How these were first made is uncertain, probably by heavy rolling of the rods, so as to make them hollow inside. These tubes were sometimes used for beads, and no other purpose for them has been noticed. In no case are they known to have been bent, to be formed into ornaments or syphons.

57. The usual mode of bead-making was by winding a thin thread of drawn-out glass around a wire, These wires are actually found with the beads still stuck on them (left, 59-61). When I say wire, I do not mean necessarily drawn wire, as wire-drawing is not known till Roman times, if then. (The piece of wire rope in the Naples Museum needs some voucher for its age.) And what appears like bronze wire, that I have found of the XVIIIth dynasty shews facets of hammering when magnified.
Many beads were imperfectly formed, and left as spirals owing to the tail of glass thread not being united to the body of the bead. These are found of a corkscrew shape, as no. 53 in the drawing on the right, etc. Some flat beads were made by coiling a long bead, flattening it, and then cutting it across, as in nos. 57, 60. The pendant beads, up to 1½ inches long, shew plainly the coils of the thread by which they were built up, in the clear structure of the glass. And every bead of this age shews more or less of the little peak at each end where the glass thread was finally separated from it. On the contrary the Coptic glass beads are all made by drawing out a glass tube, as shewn by longitudinal bubbly striations; and then the tube was rolled under an edge across it, to nick it, so as to break up into beads. It is impossible to confound a bead of the early process with one of the later.
The drawn-out glass rod was commonly used for bending into unclosed circles for ear-rings.

58. The most elaborate use of glass was for the variegated vases. These were all made neither by blowing nor by moulding in moulds, but by hand modelling. A tapering rod of metal was taken, as thick as the intended interior of the neck; on the end of this was formed a core of fine sand, as large as the intended interior of the vase. The rod and core were dipped in the melted glass and thus coated. The coat of glass was then hand-worked; the foot was pressed out into shape, like the pressed feet of the Roman glass cups; the brim was turned outward; the pattern was applied by winding thin threads of coloured glass around the mass, and rolling it so as to bed them into the body of the glass; the wavy design was made by dragging the surface upward or downward at intervals; the twisted margin of the brim, or the foot, was made by winding one thread of glass spirally round another, and bending the two round the vase; the handles were attached; and as often as the glass became too cool to work in any of these processes, the end of the rod could be just placed into the furnace, and the half-formed vase warmed up to working point. When the whole was finished, the metal rod in cooling would contract loose from the glass; it could then be withdrawn, the sand core rubbed out, and the vase would be finished.
Of the fragments of vases of which enough remained to shew the design clearly, and which had a distinct the number of pieces was—

Single-dragged . . . .160
Double-dragged . . . . 36
Twirled  . . . . . . . 36
Eyed . . . . . . . . . 42
Spirals  . . . . . . .  2
White blotches . . . .  3
Bowls  . . . . . . . .  3

The single-dragged are those only dragged in one direction on the face, forming a pattern of UUUUU; the double-dragged are those dragged alternately in each direction, forming a pattern of WWWW.
This style of glass descended into Greek times, and was largely used in Magna Graecia; but the later styles are all coarser, and have not the brilliancy and flat face that mark these earlier products, which are now firmly dated to 1400 B.C.

59. Beside the working of glass in a soft state, there was also good work in cutting and engraving. There are pieces of glass with polished faces and cut mouldings; with engraved patterns; with engraved subjects (as various rings, etc., nos. 23, 53, 133 on the right); a piece of an opaque white glass bowl, imitating fine limestone, and deeply engraved for inlaying; rich blue glass volutes for inlaying, probably in alabaster, like the blue glass and alabaster frieze of Tiryns; and hieroglyphs for inlaying in the walls, cut in glass.

60. The colours are very varied, and in sorting over hundreds of the drawn glass rods it seemed as if no two pots of glass had been quite alike; so that a few pieces of each batch might be found, but no exact match beyond those. There are purple, opaque violet, blue, green, yellow, opaque red, brown, black, and white. Most of these were both transparent and opaque; and the variety of blues and greens is indefinite.

61. Glazing was a highly developed art at this period, and reached its greatest successes under Akhenaten. Whole statues of glaze, and walls blazing with glazed tiles and hieroglyphs, shewed how the difficulties of size had been overcome.
The most complete instance of glazing architecturally that we can restore is in the columns of the painted pavement No. 1 of the harem, (on the right, below excerpt). No trace or chips of stone columns remained there; but great quantities of green-glazed tiles, ribbed to imitate bundles of reeds, (such as are upon the stone columns), lotus flowers, and buds on a triangular red ground to fit between the flowers, so as to appear as a garland of lotus flowers and buds on a red background; also lotus petals, and green or red pieces to fit between them, to appear as a white petal-wreath on green or red ground. The reed tiles have projections at the end to fit under a retaining band; and such a band on the stone columns is coloured yellow, so that it was probably of bright bronze, or gilded, on the glazed columns.

62. Inlayed glaze was also used effectively on the great capitals with gilding between, as shewn on the restoration below. On the walls glazed tiles were much used; all along the west side of the great hall of columns fragments of green tiles with daisies and thistles, were found scattered. Probably therefore there were more than two hundred feet of this tile dado, with inlayed white daisies and violet thistles. From the number of pieces of tile with water pattern, lotus, fishes, and birds, it seems that tiled floors also existed in the palace.
The stone walls were inlayed with glazed figures of birds, and glazed hieroglyphs; the latter were both small and large, some of the cartouche borders being 4 inches wide, and discs of the Aten 8 inches across.

63. Glazes were also much used on portable objects. In the palace we found many pieces of dishes in the form of half fish, half yellow melons, half green gourds, etc. These from their richness and position were most likely part of the royal table-service. Vases were decorated with inlayed patterns of different colours, and also with applied moulded figures of flowers, etc. A favourite and beautiful style was of incising and inlaying dark-blue patterns on light-blue grounds. In other cases pale green was inlayed in violet (18 above), or green in dark violet (28, 37 above).

64. But the most wide-spread and popular use of glaze was for covering moulded figures, made for most diverse uses. Finger-rings (on the right 161-240), decorations to stitch on dress (57, 59, 260, 436), inlayed hieroglyphs (241-269), pendants (271 et seq.), serpent's heads for cornices (322-327), flowers for inlaying (430, 456-506), fruits for pendants, inlaying, and ceiling reliefs (441-455), and geometrical pieces for inlayed patterns (558-594). These plates (XIV-XX) are drawn as if from the moulded objects; where the objects have been found they are indicated by the letters of the colours (v, violet; bl, blue; gn, green; y, yellow; gy, grey; wt, white; bk, black); where they are drawn only from the moulds they are marked with M. In plates XIV, XV, where the numbers are important historically, the number of examples of each individual mould are given; e.g. of No. 50 there are 4 impressions of one mould, and one each of three others, all in blue glaze; also 4 moulds of one engraving, 3 of another, and 1 of a third.
An example of these moulds is shewn at the end (595). They are rough pats of baked clay, with the mark of the palm of the hand on the back; a die was pressed on the clay, and so made the mould. After baking they were used apparently by taking an impression on a lump of moulding-paste, and then slicing the relief figure thus produced from off the lump with a sharp knife. These moulded figures were then dried, dipped in powdered glass, and fired to glaze them. Different lots of beads, etc., not yet glazed, shew that the moulding-paste was a very fine sand; so white that perhaps powdered quartz was used, where the best blue had to be maintained free from iron.

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