About the Piece

This piece is a half-scale version of the original which resides in the collection of the British Museum. I have been fascinated with the use of glass in early Egyptian times as unguent and kohl containers. I came across this bottle on the British Museum website and felt that its unique shape would be a challenge to recreate. I have paired this piece with a glass kohl applicator.

Fish with Kohl applicator: penny included for scale

Fish with Kohl applicator in the bottle

Historical Evidence

Although several fish shaped vessels have been this piece is the most complete and detailed example that has been discovered from this time period. It was found under the floor of a house in Tell el-Amarna where it was presumed to have been buried by its owner.

In general, glass vessels were functional items, used to store kohl or valuable oils. This particular vessel may have had more significance, as the Tilapia fish it represents is a symbol of rebirth and regeneration and was frequently worn as an amulet. The original piece is 14.5 cm long.(1)

The original piece was made by wrapping a stick with a clay mixture. After the clay mixture hardened, molten blue glass was then trailed onto the surface to create the body of the fish. Next, rods of white and yellow glass were used to wrap the body in stripes vertically. The stripes were then raked with a pointed tool to create the fish scale pattern. The fish was then reheated in the flame to smooth out any distortions caused by the raking. After this the eyes and fins were added to finish the fish. The piece would have then been placed in the coals of the kiln or a separate annealing chamber to allow it to cool slowly and reduce the risk of breakage.

Another kohl container featured in the collection of the British Museum is displayed with a kohl applicator in it. This particular applicator appears to be made of wood or bone. I had seen such applicators in later periods and felt that it was a plausible speculation that a glass applicator may have been used in the same time period as the vessel. I based this speculation on the following facts:

•  Simplicity of design – this applicator can be made quickly and easily by almost any level of glassworker

•  Glass applicators found in the same region in the Roman Period in Egypt . (100-200 CE).

•  Similarities in design between the applicator paired with the other vessel of this period and the glass applicators of the Roman period.

Glass Fish Vessel Reproduction Methods

I created this piece by dipping a stainless steel mandrel repeatedly (15-20 times) in bead release (a kaolin clay based mixture, similar to Kiln wash) allowing them to dry slightly between coats.

After the bead release dried completely (I waited over 72 hours to be certain that the release was completely dry) It was then introduced into the flame.

From this point forward my production method matched the theorized method of creation for the original piece. I applied the molten blue glass onto the surface to create the body of the fish. Next, I alternately applied stripes white and yellow glass using stringers to wrap the body in stripes vertically. The stripes were then raked with a pointed tool to create the fish scale pattern. The fish was then reheated in the flame to smooth out any distortions caused by the raking. After this the eyes and fins were added to finish the fish.

The piece was then been placed in the kiln to allow it to cool slowly and reduce the risk of breakage. I use a modern digitally controlled kiln, as I don't have the facilities currently to build a period kiln.

General Glass Vessel Making Methods

This vessel and applicator were made using a Minor bench burner torch and several different tools. Tools used in shaping the glass include metal shaping plates, rakes and picks. Although the tools are made of more modern materials, they are very similar to period tools.

The torch used is a surface mix torch, fueled by oxygen and propane. In period, these bead would have been made in a form of Beehive kiln, similar to the one pictured on the next page (2):

Kiln of Maccus ðe Glæswyrhta

While this particular kiln is a recreation of a Viking kiln, it is widely believed that similar kilns were in use throughout the world. A bellows system was used to drive air and create a hotter fire, and the beads would have been allowed to cool slowly in the ashes of the fire so that they would not shock. Since I have not made my own kiln yet, I annealed my beads using a modern kiln designed for bead making.

Materials

These beads are made using Effetre glass from Murano , Italy . Effetre is a soda lime glass, and the closest commercially available glass to period, which is considered a “soft” glass. The co-efficient of expansion is 104-113.

Ancient Glass

Glass is a created substance, made by heating a metal or metalloid to above the melting point and cooling it below that point without letting it crystallize. Most ancient glass was composed of silica (quartz sand), and a “flux” agent, usually soda (Na 2 O) or potash (Ka 2 O). A stabilizer is also required, usually in the form of lime (CaO). It is believed that most glassmakers of the time were unaware of the need for a stabilizer, as lime was a common element in sand. Without a stabilizer, the glass would dissolve in water. (3)

When glass is initially made, its natural color is a pale, translucent green. The addition of colorants (usually metal oxides) and opacifiers (mostly antimony, arsenic or tin) produced opaque and colored glass. (4)

I have been unable to find any texts specifically addressing Egyptian glass manufacturing techniques of this time period. However, there are surviving Cuneiform texts documenting the process for making glass in the Mesopotamian Region. These tablet fragments were found in the library of King Assurbanipal (668-627 BC) assembled in his palace in Nineveh . (5)

I have included excerpts of these texts giving the recipes for blue and yellow glass. I have not found a recipe for white glass in these texts currently.

Definition of terms for glass recipes: (6)

• Atunu - kiln
• Tersitu – a primary glass
• Tarabanu – an ingredient
• Saddu- an unknown qualification
• Busu – a primary glass
• Anzahhu – a primary glass
• Serserru – a colored glass
• Leru – ochre or orpiment
• Dusu – yellow glass
• Naga – a plant and the alkali produced from its ashes
• Dabtu- pan
• Immanakku- sand

Recipe for Lapis-Lazuli colored glass from the Cuneiform Tablets:

You keep a fire burning in the atunu for seven days. For one mina of [good(?)] tersitu (you take) three minas of tarabanu of saddu quality, [ten] shekels of busu-glass of saddu quality, five shekels of “white stuff” from the sea wh[ich is made of (?)] coral, two shekels of anzahhu, three shekels of serserru, four shekels of “male” red alum, five shekels of leru, six shekels of “white plant.” You mix (these) and grind them finely again. You collect (the powder) in a mold and out (of the kiln) will come [fine] lapis lazuli colored glass. (Postscript:) What does not become vitrified (?) enough you place (again) in the atunu [and keep] the fire [burning] for (another) seven days. (7) 

Recipe for Yellow colored glass from the Cuneiform Tablets:

If you want to produce dusu, you grind finely, separately, […] [x mina of] naga, [x mina of immanak]ku together in half a mina [of…]. [You mix them] together. [You place the mixture into a] cold [kiln which has] four fire openings and you arrange (the mixture) between its openings. You keep [a good] and smokeless [fire] burning. [As soon as the mixture(?)] begins to glow green you set (it) nearer to the fire. After it has been glowing green you take it out and let it cool off. You grind it finely [again]. [You collect (the powder)] in a clean dabtu. [You put] (it) into a cold chamber kiln. You keep a good and smokeless fire burning. As soon as (the mixture) glows yellow you stir it once “towards you.” You will see some drops form (at the tip of the rake) and when the glass is homogenous and has assumed the color of the genuine dusu stone. (8)

Bibliography

British Museum . Glass Bottle in the Form of a Fish. http://www.thebritishmuseum.ac.uk/

Francis, Peter. Asia's Maritime Bead Trade . University of Hawai'i Press. 2002.

Von Salden, et al. Glass and Glassmaking in Ancient Mesopotamia. The Corning Museum of Glass Press. 1988.

Williamson, Roland. Maccus ðe Glæswyrhta. http://www.regia.org/maccus

Footnotes

(1) British Museum
(2) Williamson
(3) Francis. p. 11, 222.
(4) Ibid, p.10-11.
(5) Von Salden, et al. p.4.
(6) Ibid, p. 87-96.
(7) Ibid, p. 41.
(8) Ibid, p.48.