an 11th-century text - Historical Metallurgy

68 Historical Metallurgy 40(1) 2006 68–88

On the Noble and Illustrious Art of the Goldsmith: an 11th-century textJochem Wolters

ABSTRACT: The 11th-century Greek manuscript, On the Noble and Illustrious Art of the Goldsmith, is characterised by an unusual equality in the treatment of recipes and techni-cal procedures. In spite of its similarities to late classical and early medieval traditions of artistic-technical writings, the tract demonstrates a great deal of independence in that it describes many methods and uses of materials for the fi rst time, and was the only reference in some cases. These include: gold plating by welding, applying niello with all the necessary steps, enamelling, etching of metals, refi ning gold with antimony, and making fi ligree. The commentary explains the substances and procedures, and outlines the status of the individual recipes within historical tradition through comparison with both earlier and later sources.

Introduction

About the manuscriptThe Parisinus graecus 2327, now in the Bibliothèque Nationale in Paris, is a collective manuscript comprising 299 pages with the arms of Henri II on its cover. It was written in Khandak (Candia = Heraklion) on Crete in 1478 as a copy of the now-lost original by Theodoros Pelecanos of Corfu, and was acquired very early by the Bibliothèque Royale in Fontainebleau where it was listed in the inventory in 1545. This manuscript, like other Greek manuscripts in Paris (Parisinus graecus 2325) and Venice (Marcianus graecus 299), primarily contains early alchemical texts and several technical recipes. However

– and most importantly – it is the only copy of the tract by an anonymous Greek titled ΤΗΣ ΤΙΜΙΩΤΑΤΗΣ ΚΑΙ ΠΟ∆ΥΦΗΜΟΥ ΧΡΥΣΟΧΟΙΚΗΣ – On the Noble and Illustrious Art of the Goldsmith (fol 280r–291r). The wording of this tract has been dated as 11th century on the basis of its similarity with the language in parts of manuscript 299.

About its contentsThe tract contains a total of 69 recipes in 57 chapters. Here for the fi rst time, problems of material ingredients

and technical procedures were given equal weight, as was not to be seen again until a century later in Theophilus’ De diversis artibus (Theobald 1984). Moreover, al-though it corresponds with written tradition, the tract demonstrates a high degree of autonomy, since it was the fi rst – and to some extent only – source to docu-ment nine technical procedures and eight applications of substances or their mixtures. Among these are the techniques of enamelling, gold plating by welding, ap-plying of niello with all the necessary steps, alloying of arsenic-containing solders, etching of metals, production of fi ligree, refi ning of gold with antimony, treating of brittle gold and silver by melting with mercuric chloride, and the production of white tin/arsenic alloys.

With the exception of three alchemical recipes (Ch 41e, 56 and 57), which are viewed as the compilations of a copyist, all the others are purely technical. As explained in the commentaries below, seven chapters are thought to post-date the main body of the work which is from the 11th century. Chapters 41–43 probably date to the 13th century and chapters 44–45 to the 15th century. Whether chapters 47–48 were also added at a later date (?14th century) is questionable, however.

69

WOLTERS:11TH-CENTURY GOLDMITHING HM 40(1) 2006

About the translationUntil recently, the tract on goldsmiths’ art had been pub-lished only once, in the original language with a French translation (Berthelot and Ruelle 1888, III: 321–37 and II: 307–322). A new translation into German has recently been published (Wolters 2004). This German translation and the present translation into English offer a commentary on the recipes, explaining the specifi ed substances and procedures mentioned, and refer to the position of the recipes within historical tradition. In as far as no initial description had been presented in the tract, reference – often multiple – to earlier sources is provided. See Table 1 for dates of these sources and for the modern texts and translations of them, full details of which are listed in the References. Of the later sources, generally only the next one chronologically has been named for the sake of brevity.

Questions of defi nition are dealt with by Berthelot and Ruelle (1888), Halleux (1981), Mertens (1995) and

Lippmann (1919), and the commentaries on the source material listed in the bibliography. In this connection, the following errors by Berthelot’s critics may be corrected: when Berthelot used ‘asem’, it is silver, gold/silver alloys (electrum, pale gold) or, in one case, a pale golden copper alloy that are indicated. Except in the alchemical Chapter 57, ‘divine water’ was used to signify ‘acid’ and once for ‘caustic’ (but not for ‘sulphur-water’, ie potassium sulphide), and ‘Roman vitriol’ actually meant vitriol rather than alum.

Chapters that contain several independent recipes are identifi ed with a chapter number and a lower case letter (such as 54a). Note, however, that in Chapter 41 these separate recipes presume knowledge of a preceeding one. References to other chapters in the tract translated here are to Ch xx, while those to chapters in other texts are to ch xx. The convention of placing clarifying additions to the text in square brackets [...] has been followed. The units of weight used in the text have the following equivalents: Pound: libra or litra = 327.45g Ounce: uncia or ouggia = 27.288g Byzantine exagion = 4.43g Karat: Byzantine keration = 0.185g

Translation and Commentary

ON THE NOBLE AND ILLUSTRIOUS ART OF THE GOLDSMITH

1) HOW TO REFINE GOLD. Take sea salt, add solid dregs [tartar], close the top of the vessel, and place it into the fi re until white hot. For every pound of metal add 2 parts sifted salt and one third sifted brick dust. Place into two crucibles, alternating layers of salt [and brick dust mixture] and gold that has been beaten as thin as possible with a hammer. Seal [lute] the whole all the way around with clay. Now place the vessel into the fi re so that the fl ame touches it. However, the furnace must be arranged as follows: take a [hollow vessel in the form of a] pot, pierce it from the middle to the sides with openings that form a cross, and attach two iron fi ttings. Place the crucibles that hold the gold [each] in the mid-dle of the cross [opening] and make an opening in the lower part of the pot [furnace] so that the slag can run out. Now fi ll the furnace with [char]coal and try to melt the gold. If the gold does [not] collect in the middle [of the crucible], begin anew the following day: soften the brick dust with salt and repeat the operation until you see the metal melt.

Documented here is the process of dry gold/silver

Figure 1: Detail from St Eloi in his workshop by the Master of the Misericordia. The earliest depiction of a goldsmith’s workshop since classical antiquity. Tools: goldsmith’s hammers, a compass, and (bottom left) a pump-drill shown here for the fi rst time in the context of metalwork. Techniques: (front right) engraving an altar cross with the graver, (rear left) hammering a circular piece to sheet metal, (rear right) operating a double smith’s bellows at an open charcoal fi re. (See forging to sheet metal Ch 4, 9, 10a, 33, 55; bellows Ch 51, 55). [see also Plate 27]

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Author Date Title Modern texts and/or translations

- 1379–1362 BC Amarna Tablets Knudtzon 1915

Theophrastus 305 BC De lapidibus Eichholz 1965

Agatharchides c113 BC De mari Erythraeo Woelk 1966; *Burstein 1989

Diodorus Siculus 1st century BC The library of history Oldfather 1935

Vitruvius 22 BC De architectura Fensterbusch 1991

Nagarjuna 30 AD Rasa-ratnakara Bein 1915, 49–52

Pliny 77 AD Historia naturalis König with Winkler 1973–96; *Rackham 1938–52

Dioscurides 78 AD Materia medica Aufmesser 2002

pseudo-Moses 3rd century Chemistry Berthelot and Ruelle 1888, II: 287–302 and III: 300–315

Philostratos 3rd century Imagines Schönberger 1968

Zosimos c300 About the same divine water Berthelot and Ruelle 1888, II: 143–145 and III: 141–143; Mertens 1995, 30–33

- c300 Leiden papyrus Halleux 1981, 83–109; *Caley 1926

- c300 Stockholm papyrus Halleux 1981, 110–151; *Caley 1927

Stephanos Alexandrinos 7th century Wolters 2000, 173

800 Compositiones ad tingenda musiva Hedfors 1932

Abu Abdalla Muhammad ibn Jahja

800 The book of mercy Berthelot 1893, III, 163–190

- 9th century Mappae Clavicula Smith and Hawthorne 1974

- 9th–10th centuries Liber Sacerdotum Berthelot 1893, I: 179–228

al-Hamdâní 942 The precious metals gold and silver Toll 1968

Constantinus Africanus after 1050 De gradibus simplicium Anon 1536, 342–387

pseudo-Gafar 11th century Book of Gafar alSaldiq’s apostle Ruska 1924

Theophilus 1122/23 De diversis artibus Theobald 1984^; *Hawthorne and Smith 1979

Heraclius 12th century De coloribus et artibus Romanorum Ilg 1873; *Merrifi eld 1849

- 13th century The handling of pearls Berthelot and Ruelle 1888, II: 352–356 and III: 368–371

Geber 1300 Liber de inventione veritas sive perfectionis

Darmstädter 1922, 103–114

Cennini 1390 Libro dell’ Arte Thompson 1960

- 1424 Sloane mss 416 Lock Eastlake 1960

14th–15th century Liber Diversarium Arcium (Montpellier mss)

Hendrie 1847, 429–430

Oviedo 1526 De la natural hystoria de las Indias Oviedo 1532

- 1532 Drey schoner Künstreicher Büchlein Anon 1532

Paracelsus 1536 Der grossen Wundartzney ander Buch Sudhoff and Matthießen 1922–73, I.10: 217–421

Biringuccio 1540 De la pirotechnia Carugo 1977; *Smith and Gnudi 1942

Dorn 1567 Clavis totius philosophiae chymisticae Dorn 1567

Cellini 1568 Trattati ... orefi ceria Milanesi 1857; *Ashbee 1898

Libavius 1597 Alchemia (Ein Lehrbuch der Chemie) Gmelin-Institut 1964 (page numbers refer to the original)

- 1705 Curiöser Künstler Anon 1703–05

- 1708 Der Künstliche Gold- und Silber-Arbeiter

Anon 1708

Notes:^ chapter numbers occasionally differ in other translations.The references in the right-hand column marked with an asterisk were not used in preparing this paper but provide English-language sources which may be more readily available to some readers.

Table 1: Classical, medieval and later sources and manuscripts cited in the commentary

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refi ning through cementation by which silver and base metals are converted into chlorides. This is mentioned indirectly in the Amarna Tablets (Knudtzon 1915: 85, 93, 139). It is described as a recovery process by Agatharchides (XXVIII), subsequently by Diodorus Siculus (III.14) and Pliny (XXXIII.84), among many others; see also Theophilus (III.33–34). A gold furnace with a cross-shaped opening is described and illustrated by al-Hamdâní (30a–b). See Ch 44–45 (below) for other gold refi ning techniques.

2) HOW TO REFINE SILVER. Make a crucible of ashes and sifted brick[dust]. Place 1 pound of silver into the crucible, cut 1 pound of lead into pieces, toss a portion of this into the crucible and heat. Quench abruptly. Now make another, new crucible of clay, and again toss in silver, heat it to white hot and quench abruptly. Take out the metal, place it into a crucible, let it melt in the fi re, and pour as [whatever] you like.

Known since classical antiquity and documented in the Leiden papyrus (ch 25 et al), this is the dry process of silver refi ning by cupellation, in which lead is oxidised to lead oxide (PbO) and forms compounds with impurities which were drawn off or, if the quantity was small, were absorbed by the porous crucible material. An untrust-worthy description can be found in Pliny (XXXIII.95). Instead, see Theophilus (III.23–24), and also Ch 31.

3) DESCRIPTION OF THE [FIRE] GILDING [OF SILVER]. Take 1 exagion of gold, pound it on an anvil so that it becomes thin, cut it into pieces, and place it into the fi re in a crucible until white hot. Then after the duration of the Lord’s Prayer, put mercury into the crucible in the middle of the gold, mix it and take [the resulting gold amalgam] off the fi re.Fill water [with alum or tartar added] into a pitcher, take the article [to be gilded] and wash it thoroughly in your hand. Also take mercury, pour it into the water in the pitcher, and amalgamate the silver until it takes on an orange colour. Now gild with the mixture specifi ed for this [see above].After you have placed [the article to be gilded] into the fi re, take it out and rub it with a brush of pig bristles. Put it back into the fi re fi ve or six times. As soon as you see the [desired] colour appearing on the surface, increase the heat and submerge it in the water. Rub it well, reheat and fi nally submerge it [again] in the water.

In contrast to gilding in classical antiquity by applying gold foil to a coating of mercury – as was clearly de-scribed by several sources such as Pliny (XXXIII.64/65/125) – the present example is a description of authentic

fi re gilding in which fi rst an amalgam is made of gold and mercury, which is then applied to the amalgamated article, and afterwards the mercury is expelled by heat-ing to around 300°C. The oldest description of this process can be found in the Leiden papyrus (ch 53–55), and later in Theophilus (III.35–39), among others. See Ch 26 for fi re gilding of bronze.

4) OTHER GILDING [GOLD PLATING] OF [SILVER] WIRE. Pour silver into a [bar] mould so that the length of the casting [ingot] is seven times [its width]. Expose the ingot to the heat so that you warm the entire length two or three times. Then smooth the surface with a small fi le of Damascus steel and [also] beat the gold very thin, so that a tight union [can] develop. Wrap the gold foil around the silver so that you can execute the union [plating], place it in the fi re and let it [become] incandescent. Then take it out of the fi re and rub it with ashes of olive-wood. Wherever gold is missing [does not adhere], press it tight with the polishing stone and return the work to the middle of the fi re. Then take it out, rub it down, and repeat this as many as three times. Now put the [gilded] ingot into the drawplate.

This is the oldest documentation of plating in which metals are welded together by the heat of the fi re, in other words they diffuse into each another and are indivisibly united. Later descriptions of this technique can be found, among others, in Theophilus (III.76)

Figure 2: Detail of the paten of the Wilten chalice. Parcel-gilded silver, the un-gilded sections with a design in niello were covered with a paste during the fi re-gilding. (See Ch 3, 26; resist medium 21, 23, 29; oxide dissolving 28, quicksilver-water 41.b; pickle 8; all for fi re-gilding. Niello Ch 5, 14b, 34). [see also Plate 32]

72


using gold plating of sheet silver as an example, and in Biringuccio (140v–141r) as the preparation for making gold tinsel. This is also the earliest reference to a drawplate, which was not mentioned again until Theophilus (III.8/75). See also Ch 33.

5) DESCRIPTION OF NIELLO [egkopsin, egkapsin, egkausin]. Take 2 parts refi ned silver and place them in a crucible into the middle of the fi re. Cover the cruci-ble with [bone ash from] mutton legs and add sulphur [but] in small amounts so that the vapours can escape [each time]. In this manner, put [it into] the crucible. Crush another portion [of silver with] sulphur, pour it into a crucible until this is half full and cover it well. Let this half [portion] melt and crush it on the anvil. [Afterwards,] pour it into a water vessel and wash it well. Then add a little [alkaline] fl ux [see below] into a lead vessel [fi lled with water] and let it boil. Next pour it into another vessel and sprinkle the work of silver or chased gold [that is to be nielloed] with soda and borax [?tzaparikón]. [After applying the niello mass,] place the work into the fi re. After you have taken it out of the fi re, polish it with pumice stone, rub it off with a feather, and warm it again with [char]coal in a clay vessel.

Although not recognised as such by Berthelot, this is a description of making and using silver sulphide niello. The washing of the niello powder, the preparatory clean-ing of the work with soda, and the polishing with pumice stone are mentioned for the fi rst time (see also Ch 14b and 34). Viscous silver sulphide niello, which according to analysis was dominant in classical antiquity – for ex-ample, the 1st century brass harness mounts from Xanten (Wolters 1997a, 171, tab 1, 1) – is mentioned for the fi rst time by pseudo-Moses (ch 47), then in the Mappae Clavicula (ch 58) and by al-Hamdâní (fol 68a–b). For other types of niello see Ch 14b and 34.

6) DESCRIPTION OF ENAMEL [smárdos]. Finely crush the enamel on the anvil, pour it into a vessel, and then wash it well. Afterwards, apply it to the chased object. Place this into the fi re on an iron oven [correct: pan] and push the prepared enamel work into the interior of the oven [furnace]. A curved, perforated sheet of iron [muffl e] must be in this oven. Press and squeeze [the bellows] until you see the silver [correct: enamel, see below] fl owing / [incorrect insert:] with the lead / on the [char]coal [fi re]. Again place the work into the fi re on the pan [see above] so that the enamel adheres [this] second time.

Although enamel was superfi cially mentioned previously – for example, enamelled Celtic harness by Philostratos (I.28.3.4–10) – this is the fi rst description of the enamel-ling technique. The text includes three easily interpreted mistakes which may have been introduced at various times: 1. the use of ‘fournellío’ indiscriminately for both

Figure 3: Detail of two of the panels on the cover of the Limburg Staurothek. Gold, cloisonné enamel. Image width 137mm. (See enamel Ch 6; enamel solder 32, and also 39).

Figure 4: Goldsmith enamelling at a furnace. With the tongs he is holding an iron pan covered with a perforated muffl e which is standing in the charcoal fire. (See enamel Ch 6; enamel solder 32, 39).

73


the pan and the furnace, 2. the confusion between silver or gold/silver alloy (electrum) and enamel (electrum as well, see below Theophilus) on the basis of a Latin forerunner, and 3. the insertion ‘with the lead’ taken from another context. The text becomes completely understandable when compared to the description in Theophilus (III.53–54) which includes the iron pan that prevents the enamel from adhering and the cover (muffl e) that protects the enamel from being soiled, for example.

7) DESCRIPTION OF THE CLEANSING [PICKLING OF SILVER]. Crumble salt and mix it with [alkaline] fl ux in vinegar. Stir well and place it onto the fi re, where it is boiled with solid dregs [tartar]. Place the tartar [see above] onto the fi re again until it is boiling well. Finally, weigh the mixture and add 2 parts burnt dregs [calcined tartar, ie potash] and 1 part sea salt. Pour it into a vessel, mix it with water, and use this to cleanse the silver.

While the earliest described silver pickle, in the Leiden papyrus (ch 64), consists of a watery alum solution, here is the fi rst documentation of a preparation with tartar and salt as its main components and with the addition of vinegar and an unknown alkali – probably soda. The same main ingredients are named by Cellini (II) and were traditional even until the end of the 18th century. See Ch 8 and 30 about other pickles.

8) DESCRIPTION OF ANOTHER CLEANSING [PICKLING PRIOR TO GILDING]. Take [alkaline] fl ux and stir it well with a great deal of salt. Together with solid dregs [tartar], place it on the fi re and put water with it. Finally calcine it, not completely however, but only until the inside of the vessel begins to turn red. Then take it [off the fi re]. After you have crushed it, mix it with water and fl ux [see above]. Add borax [?] [boráchen]. Others limit themselves to cleaning the object to be gilded with borax [?] [see above].

This recipe differs from the one in Ch 7 in that vinegar is omitted and an alkali is added which could quite possi-bly have been borax. However, this is not certain since in Europe, borax was not named as a fl ux until the Mappae Clavicula (ch 202). For other pickles see Ch 30.

9) DESCRIPTION OF THE ROYAL [GOLD] SOLDER. Take 3 parts gold and 1 part silver from an old coin, [melt this together and] pour it into a mould. When the metal to be worked [soldered] is thin, reduce [the solder] to powder, but when it [the metal] is thick, make a sheet of it [the solder]. Solder the heated wire with 2 parts of this solder and one third fl ux.

The earliest gold/silver/copper solder with a melting temperature of 938°C was documented in the Leiden papyrus (ch 30). If it is assumed that the coin silver named in Ch 9 is 80% silver with the addition of copper only, this results in a solder composition of 75% Au, 20% Ag and 5% Cu, with a high melting temperature of 975°C. The powdered solder mentioned was utilised as a dusting solder for fi ne work such as fi ligree. The sheet-form solder was cut into small pieces, called paillons, to enable better dosage.

10a) ABOUT THE ROYAL SILVER SOLDER. Take 3 exagion of silver from an old coin and 1 exagion of red [pure] copper, mix them, and place them into the fi re in a crucible. Pour into a bar mould. When the work [to be soldered] is thin, use powder[ed solder] and soda, but if it is thick, make a sheet [of the solder], solder and clean.

If 80% coin silver with copper as its only addition is as-sumed, the resulting solder consists of 40% Ag and 60% Cu with a melting temperature of 830°C. Nowhere else has such a solder been documented. About the discrimina-tion between thick- and thin-walled works, see Ch 9.

10b) [SILVER SOLDER] Others take 3 parts silver and 1 copper.

Figure 5: Goldsmith at the workbench preparing for soldering. In his left hand, he is holding the piece to be soldered, and with his right, he is taking paillons out of a dish with tongs. In the centre foreground is a borax can with a serrated nozzle containing fl ux alone or mixed with powdered solder. (See solder and soldering Ch 9–11, 24, 27, 32, 39a–b; dusting solder 9, 10a, 12, 39a; soldering paillons 9, 10a).

74


This solder, with 75% Ag and 25% Cu, which is men-tioned here for the fi rst time, has a melting temperature of 790°C. It is later on documented in Theophilus (III.73), as well as several times later during the 18th and even the 19th centuries. A solder with a very similar composi-tion (75.1% Ag, 23% Cu, and the rest other elements) has been identifi ed as early as the third century AD in a Sassanian silver dish (Wolters 1997b, 196, tab1,11).

11) ANOTHER DESCRIPTION OF SILVER SOLDER. Take 3 exagion of the silver of your choice and 2 exagion of copper. Place them into the fi re in a crucible to melt. Now add 1 exagion of tin, which you put into the middle of the crucible, let it mix together, pour onto the wire [twig broom?] attached below, and beat it fl at on a slab of marble. Now hammer it on the anvil, cleanse [it], and solder.

A silver/copper/tin solder with a fl ow temperature of c.600°C is fi rst recommended in the Mappae Clavicula (ch 210/appendix and ch 259). The solder documented in Ch 11 is composed of 50% Ag, 33.3% Cu, and 16.7% Sn with a relatively high melting temperature of around 650°C. There is no documentation of Ag/Cu/Sn solders in later periods. The molten metal was poured over a twig broom to divide it into granules, thus making it easier to portion out. Perhaps this is what was indicated here by the otherwise incomprehensible term ‘wire’.

12) OTHER, RAPID [EASY-FLOW] SOLDER OR ALAMARSA. Take red [pure] copper, approximately 2

parts red sandarac [kókkinos] from Pontus, and not quite as much wine dregs [tartar]. Take all of these ingredients and distribute the sandarac and the tartar on the copper. Crush on a [slab of] marble. Seal [lute] the crucible with clay, whereby you leave a rectangular indentation or better still a hole in the middle. The copper must be [pounded] very thin. The opening should have the size of the eye of a needle; it is intended to allow the smoke to escape upwards. After that, take [the cover] off, pour into the bar mould, and when you solder, include a quarter of the above-named ingredients. To solder [silver], take a third. Finally, place it in a crucible to melt and pour [it then] into a bar mould. Prepare [solder] in powder form. When you want to solder, cleanse and take this powder.

Our tract indicates a yellow (Ch 54a) and a red mineral (Ch 12) which occur together and both of which are extracted in Pontus in NE Asia Minor. This characteristic agrees with the statements in Vitruvius (VII.7) and in Dioscurides (V.104–105), in which yellow arsenikon and reddish sandaraka, both arsenic minerals, appear together and are mined in Pontus. The red mineral mentioned in Ch 12 (kókkinos) from Pontus is arsenic monosulphide (AsS), known as sandarac, which was called realgar in its mineral form. See more about arsenikon in Ch 54a. According to the description given in Ch 12, sandarac is heated with copper in the crucible, thereby producing a copper/arsenic alloy – of unknown composition since the proportion of copper is not given

– with the resultant release of sulphur vapour. The addition of arsenic lowered the melting point of alloys considerably. Copper with an arsenic content of 21% is a eutectic alloy with a melting point of 689°C, nearly 400°C lower than that of pure copper. This is the only historical documentation of a Cu/As solder. See Ch 24 and 39b for more about alamarsa.

13) DESCRIPTION OF HOW TO GIVE A GOLDEN COLOUR TO AN OBJECT. Take earth that is called ochre, put it on the fi re until it turns red, then take it and stir it in water with sal-ammoniac. With this, dampen the object that you want to gild [give a golden colour], place it into the fi re and repeat [this] until smoke is produced and the [desired] colour appears; then plunge it into water [to rinse].

The coloration of metals by coating with metal oxides in watery sal-ammoniac solution, or something similar, which are then reduced to pure metal in the fire, ie united with the surface of the base metal, is one of the oldest methods of coloration. The red ochre designated in this recipe for this purpose is red chalk (ruddle), Fe

2O

3, which later became an ingredient in yellow and

Figure 6: Metallurgically-important substances in the pictorial language of the Ortus Sanitatis (Mainz 1491). L to R, above: tutty/zinc oxide (See Ch 50, 55), tartar (Ch 1, 3, 7, 8, 12, 14a, 16b, 25, 30, 35), realgar (Ch 12, 54b) together with orpiment (Ch 20b, 54a); below: alchanna (Ch 20b), curcuma (Ch 35, 55), gum arabic (Ch 20a–b), traganth (Ch 39a).

75


red annealing waxes, and is documented here for the fi rst time in this context. Not until Cellini (XXVIII) is a red chalk/sal-ammoniac mixture, with the addition of verdigris, saltpetre, and vitriol, described again as a colorant for metal.

14a) GIVING A GOLDEN COLOUR TO A SILVER OBJECT: [SO-CALLED] GILDING. Grind equal parts of sulphur, garlic, and wine dregs [Tartar], add dry wine dregs [cal-cined tartar, ie potash?] with urine and salt; heat it in the fi re and place the object to be gilded into the middle for the duration of the Lord’s Prayer. Then take it out and plunge it into cold water. Repeat fi ve to six times so that the colour can penetrate deeply into the object.

Garlic juice, urine, etc are documented as ingredients in a preparation for gold coloration in the Mappae Clavicula (ch 197), although there a sulphide patina is created with metallic additives. As ingredients in a pickle for gilding, garlic juice etc are mentioned in Cennini (ch 153). However, the present chapter gives a description of coloration with vegetable pigments, as is documented in the Leiden papyrus (using caraway as an example in ch 27/46, and mangel root in ch 45).

14b) [NIELLO PROCESS FOR SILVER]. To fuse [niello], mix 3 parts old coinage metal [silver coin] and a quarter [of the mixture] lead, place it into a crucible and melt with an excess of sulphur, while you keep the crucible covered.

Berthelot did not recognise this recipe as niello on the basis of silver/copper/lead sulphide. Assuming coinage silver with 80% silver and the rest copper, the resulting metal content of 1.0 Ag:0.250 Cu:0.417 Pb was not mentioned anywhere else. In contrast to pure metal sulphides, the more easy-fl owing Ag/Cu/Pb-sulphide is fi rst documented as a niello mixture in the Leiden papyrus (ch 35). However, it has not yet been identifi ed analytically earlier than the Middle Ages, eg a gilded silver Byzantine amulet from the 11th century, (Wolters 1997a, 171, tab 1, 38). For other niello recipes see Ch 5 and 34.

15) TO [REDUCE] SHINE IN SILVER [BLACKENING]. Take sal-ammoniac and verdigris, dissolve them in vinegar, coat the work of silver with it, [and place it] in the sun; it will immediately turn black. If you do not have these ingredients on hand, blacken silver with smoke from a torch.

Verdigris consists of a mixture of basic copper acetates and can easily be reduced to metallic copper. Therefore, it was utilised quite early as a colloid solder and also as

an ingredient in annealing wax for gold coloration as well as for the chemical coloration of copper and bronze. For blackening silver alloys, verdigris is documented here for the fi rst time. The effect is primarily due to the dark compounds formed by the copper component of the silver alloys.

16a) OBSERVATION [CLEANSING OF COPPER]. The copper is cleaned with astriosiaké [?] and with the juice of plantain; I mean the broad-leaf plantain.

Plantain (plantago major) contains silicic acid, the gly-coside aucubin etc as active ingredients. Its astringent effect was emphasised by Dioscurides (II.126).

16b) [FLUX FOR SILVER]. The silver is cleaned and made supple with soda [salonítrion]. Place silver with this substance [literally: solution] into a crucible and add a fl ux obtained from solid wine dregs [calcined tartar, ie potash].

In spite of the misleading term ‘solution’, it can be in-ferred from the utilisation of the crucible and the absence of table salt, a typical ingredient of historic silver pickles (see Ch 30), that this is a reference to reductive smelting of silver and not to pickling. Soda (Na

2CO

3) and potash

(K2CO

3) are highly water soluble, and thus are effective

de-greasing and cleansing alkalis. These are utilised as reductive smelting fl uxes to dissolve silicates and metal oxides on precious metals. Soda is the oldest fl ux for soldering and smelting mentioned, for example in Pliny (XXXIII.93) and in the Compositiones (Y34–Z3), and was not generally displaced by borax until the 16th century. Both Pliny (XIV.131) and Dioscurides (V.114) report potash as a substitute for soda and vegetable ashes. The Mappae Clavicula (ch 202) fi rst documented potash as a component in a fl ux mixture. Theophilus used potash as a universal flux for hard soldering (III.31/60/73/91).

16c) [SAL-AMMONIAC]. The sal-ammoniac cleanses [?] the silver in the crucible.

Sal-ammoniac (ammonium chloride, NH4Cl) is eas-

ily dissolved in water. When heated, it decomposes at 355°C into ammonia (NH

3) and hydrochloric acid

(HCl), hence its acidic effect. Sal-ammoniac is first mentioned by Nagarjuna (ch 3) and was known to Abu Abdallah Muhammad ibn Jahja (CVXXVII.187) in the Arabian world (Wolters 1997b, 192). The earliest European source indicating knowledge of sal-ammoniac is the Liber Sacerdotum (ch 158). Theophilus was not acquainted with this substance.

76


17) MYSTERIOUS RECIPE [GOLD COLOURED ALLOYS]. Take some silver and a little verdigris until you have as much silver as you need and crush them together. Toss them into a crucible on [together with] either tin or copper and a true gold will be created.

Since no quantities are indicated and verdigris is re-duced to metallic copper in the crucible, it is apparent only that in one case a silver/copper/tin alloy is cre-ated, and a silver/copper alloy in the other. Tin bronze, consisting of 85–87% copper and the rest tin, is gold coloured. As the copper content is increased, silver al-loys become noticeably more yellow, as for instance the eutectic alloy of 71.9% silver with copper (see Ch 40a). A reduction of verdigris for the production of ‘golden’ surface alloys cannot be taken into account here because of the processing in the crucible. The documentation of this recipe is apparently incomplete.

18) ABOUT THE PRODUCTION OF DESIGNS HOLLOWED OUT [POIEZAI PHOURMAS] [ETCHING OF METALS]. Make a casting with metals. Melt them [right] there where the mould is standing. Smooth the area [to be etched] well, namely the surface of the cast-ing, either with a fi le or with the help of a lathe. Apply a thin coating of wax to the surface where you want to make the etching, then form a ring with the wax all around [the area] to contain the liquid [see below]. Now take a fi ne needle and scratch the design [to be etched]

– letters for example – into the wax, whereby you [must] be careful that the needle penetrates well into the form [wax coating]. Now rub [together] silver [correct: subli-mate = mercuric chloride] and verdigris with lemon juice and pour some of this onto the [wax-covered] casting, [for example as] onto the circularly arranged letters of a coin, whereby you [must] proceed so that none runs over. If you want a deep etching, let it [stand] overnight. However, if you do not want a deep etching, leave it for half a day. After you have removed it [the wax coating], you will fi nd the etching acceptable, since this method will etch the metal suffi ciently.

This is the earliest recipe for the etching of metals. The origins of this technique have been very little researched. Early examples stem probably from the late La Tène period (Hoops 1973, I: 475). Verdigris is not mentioned again as a classic ingredient in etching acids for iron and steel until the Venetian Sloane mss 416, and the Drey schoner Künstreicher Büchlein (12r–v). As an ingredient in aqua fortis for silver and copper etching, it is still recommended in the Künstlicher Gold- und Silber-Arbeiter (170/173). Cellini (XXXIV) describes an etching liquid which is also based on sublimate (HgCl

2),

verdigris, and lemon juice to which he adds alum and vitriol (see Ch 41a). The gold coloration technique of pre-Columbian cultures, admired by the Spanish (Oviedo 1526, XLVIv), was based on the utilisation of vegetable acids which dissolved the copper component out of the gold alloy and converted it into easily water-soluble oxalates. In a similar manner, in this recipe the lemon juice on the surface converts metal into highly water-soluble citrates. The solubility of silver in lemon juice was proved experimentally by Marggraf (1768, 108). The recommendation to add ‘silver’ makes no sense in this case. It was probably confused with sublimate. It may be indicative that at this point, instead of the usual terms ‘argros’, ‘argroy’, or ‘asemos’ for silver, the tract used the Latinate form ‘artzènto’ = argentum, which could understandably have been mistaken for ‘argentum vivum’ (sublimate) when employing a Latin forerunner. That sublimate was actually intended, is corroborated by comparable recipes (see above, Cellini). The practicability of the recipe was experimentally proved by the author on copper, brass (with 37%Zn), and 93.5% silver. Beeswax was used as the resist and soda as the alkali. After 24 hours, the etching with lemon juice and verdigris produced good results, while an even better effect was produced by etching with lemon juice and equal parts verdigris and sublimate. Etching with lemon juice alone produced good results, but only after etching for several days. In all cases, the etchings were characterised by a high degree of fi neness, ie there were no uneven edges and even the most delicate lines could be etched. With the use of sublimate, conspicuously light, white edges appeared within the etched areas. Corresponding observations on medieval goldsmiths’ works could not be explained until now.

19) ANOTHER [RECIPE] FOR WRITING IN GOLD [COLOURED] LETTERS. Crumble cinnabar [correct: gold coloured lead oxide] into the dish [needed for the procedure]. Then put egg white into a vessel, add water, beat well so that it becomes foamy, and wait until the egg froth collapses. Then take [some] of the egg liquid and mix [it] with [the contents of] the dish. Place it wherever you like, and as soon as it has dried, put the rest of the egg white into the dish. Expose [the inscription] to the air and as soon as [it] is dry, clean it and polish with the buffi ng stone.

Cinnabar, which is unsuitable for gold ink, was often confused earlier with yellow lead oxide. The Leiden papyrus (ch 34) gives a recipe for gold ink with gold coloured lead oxide but with the addition of alum and no mention of egg white, a universal, well-adhering bonding agent. The Mappae Clavicula (ch 30–31)

77


describes recipes for gold ink that included yellow lead oxide and gold dust. The polishing with a buffi ng stone mentioned here is adopted from gilding with gold leaf. See Ch 20a–b and 49 about gold inscriptions.

20a) HOW TO MAKE [GOLD] INITIALS IN BOOKS. Take pure fi ne gold, mix it with silver, and place it into the fi re in a crucible. // [excursus?] Then take sulphur [correct: gold-coloured lead oxide?], mix on a porphyry [slab], grind it as well as you can until it is fi nally as fi ne as fl our. // Pour everything onto a polished tablet of clay and place it into a gentle fi re, whereby you [should] cover it with a clean ceramic vessel. Pay attention that the product is heated to red hot. Then let it cool down and mix it with the help of a sponge and a great deal of water on the porphyry. Put everything into a clean vessel and let some [time] pass, so that the cleansed preparation can settle. Add water and wash until the foreign matter is cleaned [washed out]. When you want to write, add gum [arabic] to water in the evening and bring it to a boil with the gold.

Gum as a bonding agent for colours is mentioned in Pliny (XIII.66–67). The Leiden papyrus (ch 51/76) describes gold applied with gum for writing. This is produced, for example, by powdering high carat gold leaf and gold alloys (ch 44/68) to which lead is added in one case (ch 68) to make the gold alloy more brittle and thus easier to pulverise. Possibly the sulphur mentioned in Ch 20a, which is unsuitable in this context, was confused with yellow lead oxide that was easily reduced to metallic lead in the heat. However, it is more likely that the passage on sulphur was written into Ch 20a through confl ation with another recipe. For example, the Leiden papyrus (ch 70/71) lists sulphur as an ingredient in gold-coloured inks. See also Ch 30 about sulphur as a pigment, and Ch 19, 20b, and 4 about gold inscriptions.

20b) [GOLD COLOURED INITIALS]. For this, first draw the initials and then use another preparation, which you obtain when you mix together ochre, gum [arabic], alchanna, and cinnabar [correct: sulphur or orpiment]. Now sit down at the [pre-drawn] initials, write with a paint brush, as is the custom, and accent the gold [letters].

The Leiden papyrus describes eight recipes for gold-coloured inks from surrogates. Most similar to recipe 20b is the one in ch 56 that recommends a mixture of orpiment (As

2S

3), white gum, saffron, etc. As a vegetable

pigment, alchanna is specified instead of saffron in recipe 20b. Alchanna or alkanet, a red dye which is the main ingredient in alkannin, was obtained from the root of the boraginaceous plant Alkanna tinctoria (alkanet, orcanet). The plant is described as a dye in Pliny (XXVI.116), Dioscurides (IV.23), the Stockholm papyrus (ch 93/133/138), and the Leiden papyrus (ch 89–90/97/133). See Ch 35 about vegetable pigments, and Ch 19, 20a, and 49 about gold inscriptions.

21) [HOW TO] APPLY GOLDEN ANIMALS ONTO A DISH, A PART [THEREOF] OR ANY OTHER NON-GILDED OBJECT [RESIST TECHNIQUE FOR PARCEL GILDING]. Take mutton bones [and] calcine them until they turn to ashes. Then mix some gypsum with white lead [lead carbonate] and grind it thoroughly until it is well blended. Add fi sh glue. Apply [all] this to the areas that you [do not] want to gild and [wait] until it is dry. Then gild the rest.

As a resist coating for fi re gilding, Theophilus (III.73) mentions a mixture of clay, salt, and brewers’ yeast, Heraclius (III.15) recommends lamp black, salt, and egg white, while Cellini (XXXIII) describes fl our dust mixed with water, or gypsum and fi sh glue as an alterna-

Figure 7: The Lombard queen Theodolinda visits a goldsmith’s workshop by Franceschino, Gregorio, and Giovanni Zavattari. In the left foreground, goldsmiths are smashing an idol, a donation from Theodolinda, for material to make liturgical vessels; right foreground, goldsmiths are working on handled chalices; right background, one is holding a vessel in the fi re while another watches. [see also Plates 28 and 29]

78


tive. These similarities indicate that what is described in Ch 21 is a preliminary stage of fi re gilding. See also Ch 23 and 29.

22) ABOUT COLORATION IN THE FIRE. Two parts silver from an old coin and 3 parts copper.

If one assumes 80% silver coinage alloyed only with copper, this recipe produces an alloy consisting of 32% Ag and 68% Cu. The high percentage of copper results in the formation of copper oxides when heated to incan-descence. The intended use is unclear.

23) DEPICTING ANIMALS ON A DISH SO THAT THE BACKGROUND REMAINS WHITE [RESIST TECHNIQUE FOR PARCEL GILDING]. Take egg white and sifted brick dust without dampening [add no water]; paint over the background and place in the sun to let it dry. Then gild the animals.

For commentary see Ch 21 and 29.

24) [RECIPE] FOR GOLD SOLDER [AND SILVER SOLDER]. Take 1 part alamarsa and 2 parts gold. To [solder] silver, take 1 part alamarsa and 2 parts silver.

This recipe cannot be interpreted exactly since the precise composition of alamarsa (identifi ed in Ch 12 as a Cu/As solder) is unknown. The products would be a brittle gold solder, of Au/Cu/As, or a silver solder, Ag/Cu/As. Both alloys are historically documented only in the present source. See Ch 12 and 39b about alamarsa.

25) ABOUT THE PROCEDURE FOR GILDING [GIVING A GOLDEN COLOUR TO] COPPER WITH SILVER. Break up fi ne silver and cut it into small pieces. Then do the same as [with] gold when you add mercury, amalgamate, and gild. Add solid wine dregs [tartar], pour it into oil, and let [it] boil. After that, place the dish into the middle and leave it there for a while. Then add cotton [?] and stir. Finally place it into the oil and stir until the mercury has collected in the middle of the oil.

The fi rst part of the recipe describes the fi re silvering of copper. How this silver layer is coloured golden is not clear. It could be imagined that boiling in oil created a thin layer that had the effect of a yellow-gold varnish.

26) ABOUT THE GILDING OF AMALGAMATED BRONZE [FIRE GILDING OF BRONZE]. In order to amalgamate [to fi re gild], take nice pure asem [elec-trum with the colour of a] lemon or orange, put it into [a solution of] wine dregs [tartar] to make it shiny. Then

put [your] amalgamated bronze with it and place it above the electrum. [During the production of the amalgam] the gold dissolves almost immediately in the mercury. [After you have applied the amalgam to the bronze] then place it over the fi re on a large, clean, polished sheet of iron. Rub it down with a rabbit’s foot. After this, when you see that the colour is adhering, take a wolf’s tooth for pressure polishing over the fi re, and gild [in this manner].

This is an incomplete description of the fi re gilding of bronze on the basis of an amalgam of mercury and the naturally occurring pale gold alloy, electrum. The work is placed onto the fi re on a sheet of iron as mercury does not amalgamate with iron. Pressure polishing with hard stones such as haematite or with teeth from beasts of prey was common practice. The term ‘amalgamate’ is used here both for the preliminary treatment of the bronze with mercury water (see note to Ch 41b) and for the fi re gilding itself. See Pliny (XXXIII.80) about electrum, a naturally occurring gold/silver alloy of 20% or more silver, and Ch 3 for gilding silver.

Figure 8: Detail of fl abellum on a cross. Cast copper, parcel fi re-gilded. The typical edges of gold amalgam application with a bristle brush are plainly visible at the places where strips of gilded silver once covered the arms of the cross and the outer ring. (See fi re-gilding Ch 3, 26, as well as resist medium 21, 23, 29, oxide dissolving 28, quicksilver-water 41b, and pickle 8, all for fi re-gilding.) [see also Plate 30]

79


27) [SOFT] SOLDER … [omission by Berthelot and Ruelle 1888] First prepare a solder by putting 2 parts tin and 1 part lead into a crucible. When everything is melted together, add some sal-ammoniac and fi nally small fi lings in order to make the solder. Put everything onto [a] marble [slab], quickly gather the pieces [to be soldered] and also arrange them in order on the marble to be able to solder them together.

This is the historic soft solder with the lowest melting temperature that has been documented. The alloy of 33.3% Pb and 66.7% Sn has a melting temperature of 192°C. The same composition for soldering tin is mentioned for the fi rst time in the Compositiones (X5–6). Theophilus (III.75) recommends it for soldering cop-per. Both uses of this solder can be authenticated until well into the 18th century. Soldering on a marble slab, instead of in the fi re, indicates the use of a soldering iron or something similar. One could conceive of fi lings of horn, which contains ammonia and was used for the production of salt of hartshorn (ammonium carbonate), as a fl ux. See Ch 16c about sal-ammoniac.

28) [OXIDE-DISSOLVING EFFECT OF WAX IN FIRE GILDING]. If you gild silver and the gilding does not adhere, [then] before heating, take a feather and distrib-ute some pure wax over the silver, then gild.

Because of its main components, palmitic and cerotic acids, wax acts as an oxide-dissolving fl ux. In the same manner, for example, palm oil with its palmitic acid content has been utilised as an ‘acid free’ fl ux for the production of tin plate until modern times.

29) HOW TO GILD ANIMALS ON A DISH [SO THAT THE BACKGROUND REMAINS PLAIN]. Take hide glue and some lime and melt it on the fi re. Then paint the back-ground [with this preparation] with the aid of a feather. When the metal [of the background] is covered [with the glue/lime mixture], rub mercury into the animals.

Since this is apparently a fi re gilding process, the designs are not painted with pure mercury, but rather with a gold/mercury alloy, ie a gold amalgam. If pure mercury were applied, it would be covered with a layer of gold leaf. About the latter, see the commentary following Ch 3. See Ch 21 and 23 for similar resist coatings for parcel gilding.

30) ABOUT [THE PROCESS OF] GIVING GILDED SILVER A LOVELY COLOUR. Take 3 parts sulphur, 2 parts dregs from [Greek] Malvasian wine [tartar], and 1 part salt. Crush this well and let it boil thoroughly with

water. Then dip the silver into the middle and leave it there for the duration of the Lord’s Prayer. Then take it out, rinse it in cold water, and brush [it].

Except for the absence of garlic, this recipe is essentially the same as the one in Ch 14a. Sulphur as a pigment for gold-coloured inks is documented in the Leiden papyrus (ch 70/71). See also Ch 20b and 35.

31) WHEN SILVER IS CONTAMINATED [REFINING OF SILVER BY CUPELLATION]. Put coarsely crushed brick into a crucible [with the silver] and heat until the metal is melted. Blow onto the crucible from above with a blow pipe: the lead will be absorbed [by the brick material]. When the metal is [still] not purifi ed, repeat the opera-tion. Now pound [the metal] with a hammer and if it is [still] contaminated, add mercury and pieces of broken brick and put it into the crucible again.

The same procedure was described in Ch 2 (see the commentary there) with the difference that here, mercury is added for stubborn contamination. Amalgamation in connection with the extraction of silver is fi rst described by Biringuccio (47v). The mention of a blow pipe, a precursor of the modern soldering blow pipe, in Ch 31, is the fi rst European reference since classical antiquity. In the Arabian cultural area, the blow pipe is also documented by pseudo-Gafar (Ruska 1924, 103). The

Figure 9: Goldsmiths depicted as cherubs, with a blowpipe and a bag (skin) bellows at the furnace. These are mentioned in the tract for the fi rst time since classical antiquity. Byzantine examples retained the same appearance as these Roman ones, a millennium earlier. (See blowpipe Ch 31, 51; bellows 55, 51).

80


application of a stream of air from above provokes the oxidation of lead to lead oxide, which in this case is absorbed by the coarse brick material. See Ch 46.

32) ABOUT ENAMEL SOLDER. Take 10 parts fi ne silver and 1 part copper. Add some fl ux [borax?] and proceed as you like: crush it fi ne, cleanse [the area to be soldered], and solder.

Silver alloys that are suitable for enamelling have a high silver content with a correspondingly high melting temperature and therefore require solders that also have a high melting temperature. Today 97% silver with 3% copper (melting point 940°C) is preferred as a material for enamelling. The solder documented here with a composition of 90.9% Ag and 9.1% Cu has a melting point of 875°C and is the most diffi cult to melt of all the silver/copper solders that are historically documented. It should be emphasised that here the solder is handled in powder form mixed with a fl ux, a practice that later became widespread.

33) ABOUT [THE PRODUCTION OF] FINE [SILVER] WIRES. Take fi ne silver, hammer it [to a sheet], cut it into pieces [strips], and put it into an iron vessel with a round bottom [for soft annealing]. Afterwards, draw it through the drawplate one time. Work on it with the fi le

… [omission by Berthelot and Ruelle 1888], add white fl ux [borax?], and solder.

Here the description of the production of fi ne wires, such as were needed for fi ligree work, mentions the drawplate, which is unusual for this period. The silver is heated in an iron vessel since these metals would not melt together if accidentally over-heated because of their lack of re-ciprocal diffusivity. See commentary to Ch 4.

34) ABOUT THE MAKING OF NIELLO. Take 1 exagion of fi ne silver, 1 exagion of copper, and 1 exagion of lead. Melt it in a crucible, add a large amount of fi nely ground sulphur, and pour it into a new vessel. Leave it in liquid form until the smoke has escaped. After cooling, pour with [the addition of] sulphur into a bar mould [to form] an ingot. Then crush, wash, and use it wherever you like.

This niello mixture is first described in the Mappae Clavicula (ch 56/206) as ‘painting’ on gold to resem-ble inlay. It can allegedly be found in the Montpellier manuscript (Rosenberg 1924, 2, 6) where ‘painting’ was mentioned again (Hendrie 1847, 429–430). See Ch 5 and 14b for other niello recipes where the fl ux is also not named.

35) ABOUT [THE PROCESS OF] GIVING GILDED SILVER A LOVELY COLOUR. Take yellow curcuma [turmeric], grind it fi ne, and add it along with dry tartar to water prepared on the fi re: I mean the dregs from Malvasian wine 7 [tartar] and some salt. Then leave the object in the liquid for the duration of the Lord’s Prayer. Afterwards, take it out and plunge it into cold water. Repeat two or three times.

Turmeric (Curcuma longa) is a plant of the ginger family which contains the yellow curcuma dye in its rhizome. The plant was also called Indian saffron and its pigment was used as a saffron substitute. In this recipe, colora-tion takes place through vegetable pigmentation as in Ch 20b (qv).

36) ABOUT THE PROCEDURE FOR CEMENTING SMALL VESSELS BACK TOGETHER; PRODUCT FOR JOINING CLAY PIPES. Pour [water over] sifted lime and wet it well for several days. Then put the slaked lime [into a vessel]; also boil mutton bones and heads, and pour the liquid thus obtained [hide and bone glue] over the lime. Boil again an extract of elm bark [?], add egg white, [stir well] and cement together whatever you like.

The mixture of lime and hide glue has been described in Ch 29. Lime is still in use today in the production of

Figure 10: Goldsmith’s apprentice drawing wire with tongs. He is standing on the drawing stool holding the drawplate with his feet. (See wire drawing and drawplate Ch 4, 33, 39a).

81


casein glue. Here, egg white and an extract of tannin-rich elm bark are also added to make glue or cement for ce-ramic ware. The Mappae Clavicula (ch 122B) describes a similar cement for stone made of marble powder, fi sh- and cattle-glue, ie glue from cowhide and bones.

37) HOW TO GIVE [BACK] LUSTER TO A GENUINE PEARL. Take a watermelon or a cucumber, open it in the middle, lay the pearl inside, and place the cucumber on the oven until it disintegrates: this will return the lustre to pearls.

A similar recipe is documented in The Handling of Pearls (ch 7); the pearls are inserted into an onion or a similar bulb, wrapped with bread dough, and placed on the stove. In both cases, the fermentation process should have provided a cleansing effect. The fermenta-tion process of a melon is also mentioned in Dioscurides (II.135). See Ch 38 and 48.

38) ANOTHER [RECIPE]. Let the genuine pearl steep in a bird or a young pigeon and remain there for the duration of the Lord’s Prayer; then press [on the body of the bird] to get it back.

The Stockholm papyrus refers to the Indian origin of this method, includes similar recipes in which the pearl is to be swallowed by a hen (ch 25) or a rooster (ch 60). The Handling of Pearls (ch 5) recommends coating simulated pearls with honey, giving them to a caged bird to swallow, and then feeding the bird with grasshoppers to make it ex-crete the pearl. Der Künstliche Gold- und Silber-Arbeiter (262) describes a similar procedure with pigeons. In all of these cases, the cleansing action probably resulted from the digestive juices of the birds. See Ch 37.

39a) ABOUT GOLDSMITHS’ WIRES [MAKING FILIGREE]. Take fi ne silver, make it more pliant through [the addition of] one seventh of its weight in lead so that it becomes as supple as gold. Then cleanse it and pour it into bars [ingots]. Forge it to double its length. After that, make wires from it, [and form] leaves, twigs, stars, roses, entwined and interwoven meshes, animals, birds, and every other design that pleases you. You should have a thin iron [sheet] of uniform thickness available. Take tragacanth, put it into a vessel together with water, and let it soak over night. The [following] morning pour off the water: place it [the soaked tragacanth] on the fi re to make it readily available and to give it a pasty consistency. Then take depilatory tweezers and lay the wire [ornaments] and leaves into the glue [tragacanth] one after the other. Then take them out again, organise them on the iron sheet [see above], and create whatever

you like with them. As soon as you have completed this, place it into the fi re until the glue [tragacanth] is slightly charred.[In order to alloy the solder,] now add 1 exagion of fi ne silver [to the metal X], place it into a crucible and let it melt.To solder, pound it with a hammer as thin as you can, cut it with scissors into tiny pieces [soldering paillons], and apply this solder onto the [thick] wires with the help of a dampened feather. After this, make coarse fi lings [dusting solder], scatter these [onto the thin wires], and dust them with fi nely ground fl ux [borax?]. Expose it to the fi re. Then clean and polish [the portions] that were not treated [soldered]. / Finally, cleanse by adding 2 karats of washed copper mineral [copper sulphate?] or misy [iron sulphate] … [omission by Berthelot and Ruelle 1888].

This is the earliest description of the process for mak-ing fi ligree. Later examples are in Theophilus (III.52), Cellini (II) and Biringuccio (135v). In Ch 39a, the desig-nated alloy consists of 85.7% Ag and 14.3% lead. It has a melting temperature of about 842°C, and becomes hot short (brittle) when heated above 304°C because of the lead content. Therefore an error can be assumed. Before soldering, the bent wires are glued with tragacanth, a gum resin from Astragalus L, which is mentioned by Theophrastus (9.8.2/15.8). It is fi rst recommended for this purpose in the present source and then later by Cellini (II). When heated, the tragacanth carbonises and has a reducing effect. The heating takes place on an iron sheet since iron and silver would not diffuse into each other or stick together if accidentally overheated (see Ch 33). For the solder used here, the content of base metals is omitted. A silver solder such as one of those described in Ch 10a-b or 11 can be considered. Since fi ligree is made of wires of different thickness, they are soldered with solder of varied consistency, ie heavy wire for the main framework with solder in the form of sheet metal snippets, called paillons, and the fi ner wires with

Figure 11: Detail of Golden Shapka of Monomach. Filigree headpiece, partially with granulation on wire. The gems and pearls are later additions. Image width c70mm. (See fi ligree production Ch 39).

82


powdered solder; see Ch 9. The last sentence is probably due to faulty compilation or is the addition of a copyist, since both materials in this combination are unsuitable for cleansing and their utilisation would cause unwanted discoloration of the metal.

39b) [SOLDER]. Where no enamel has been applied, use this solder – it can be produced from old coins – or [use it] everywhere alamarsa comes into play.

This is a sentence out of context, probably from another recipe. See Ch 12 and 24 about alamarsa.

40a) ANOTHER MYSTERIOUS METHOD. Take un-slaked lime, mix oil into the lime, wetting it thoroughly once or twice. Then pour it into a distillation vessel [alembic]. Also add a caustic solution [?], whereby you pour it all over until [it is] two fi ngers [deep]. Now fi ll this divine water into another fl agon. After that, take a linen cloth and dampen it with this water and expose it to the fi re. If the cloth burns, you know that it was not prepared well. Make the lime preparation again with other [un-slaked] lime and repeat as before until successful, ie until the fabric no longer catches fi re.

Un-slaked lime has been a component of widely varied fi re-proof products through the modern period. See the Curiöser Künstler (I,133/257/305/348).

40b) [GOLD-COLOURED ALLOY]. Now take oil, add tin into the crucible and gold[-coloured alloy] will form.

This is a fragment of a recipe for the production of a golden-coloured alloy containing tin. The tin bronze with 85–87% copper, the rest tin, is a modern example of a gold substitute (Deutsches Reichspatent 54846). See Ch 17.

41a) ANOTHER DIVINE WATER [NITRIC ACID]. Take 1 pound of vitriol [chálkandos], 1 pound of saltpetre [salonítrion], and 4 ounces of cinnabar, crush them in a stone mortar, pour them into a distillation vessel [alem-bic], and place it on the fi re. Seal [the distillation vessel] with a paste of sourdough and egg white. Set aside the fi rst water [that remains in the distillation vessel]. As for the second water, [ie] that which runs out of the distil-lation vessel after it has been condensed in the alembic; this is what is called aqua fortis [nitric acid].41b) [QUICKSILVER WATER = MERCURIAL SOLUTION]. Now take 2 ounces of both waters, add 2 ounces of quicksilver, place everything together in a fl ask into hot ashes, and quicksilver water [mercury nitrate solution] will form.

41c) [SILVER NITRATE SOLUTION]. After this, take 1 ounce of the water that is left [nitric acid] and 1 ounce of fi ne silver, put everything into another fl ask and silver water [silver nitrate solution] will form.41d) [SILVER NITRATE AND MERCURY NITRATE CRYSTALS]. Now mix the two waters, the quicksilver water and silver water, together in another fl ask, leave it open, and place it into hot ashes: a material as white as crystal will form. 41e) [ALCHEMICAL OPERATION]. Take as much as you want of these crystals, [add] the same amount of lime oil [lime distillate] and an equal amount of quicksilver, pour them into another fl ask, sprinkle them well until the quicksilver is dissolved. Now pour everything into a distillation vessel [alembic], make a weak fi re, pour off the water [liquid] that escapes from the distillation ves-sel three times, and each time add [lime] oil by pouring it over [the contents of the fl ask]. After you have done this three times, you will see that a sort of stone will have formed in the distillation vessel [alembic]. Take 1 ounce of this material and 1 ounce of quicksilver and what you desire will happen.

This chapter was apparently added by a later copyist, since the operations described were not known until the 13th century. a: Aqua fortis has been produced since the 13th century from saltpetre and vitriol (iron sulphate or less often copper sulphate) or with alum as a substitute. The proc-ess is fi rst described by Geber (XVII/XXI/XXII), and still mentioned by Biringuccio (63v–66r). It is documented again by Cellini (XXXIV), where verdigris, lemon juice, and sublimate (ie, HgCl

2) are added along with the vit-

riol and alum, and the acid is used for metal recovery and for copper etching. In Ch 41, cinnabar (HgS) is added instead of sublimate. About aqua fortis (nitric acid) see Ch 42–43. b: Quicksilver is dissolved in nitric acid resulting in a solution of mercury nitrate, also called quicksilver water, which was used to prepare base metals for fi re gilding, among other things. When metals were dipped into this solution, a thin layer of mercury formed through ionic exchange to which the gilding adhered. c: Silver is dissolved in nitric acid to form silver nitrate. d: Silver nitrate and mercury nitrate form colourless crystals by evaporation. e: Lime oil is defi ned by Libavius (1597, 335) as lime (CaO) distilled in a lengthy process from an alcoholic lime solution. When combined with acids, the prepara-tion decomposed, releasing carbon dioxide. All in all, this part of the recipe is difficult to understand and apparently describes an alchemical procedure with the goal of transmutation.

83


42) WATER FOR RECOVERING GOLD FROM SILVER [NITRIC ACID AND APPLICATION]. Take 2 parts sal-am-moniac and 3 parts saltpetre; grind them well in a mortar. Then put them into a distillation vessel [alembic], seal this with [a mixture of] ashes, brick dust, and eggs, place it on a stove, and let it boil for three hours. After this, open [the distillation vessel] and take out the preparation, put it back on the fi re and let it boil for the duration of a long night until dawn, The length of time is [a maximum of] 65 hours and the fi re must be gradually increased. Using this method, the divine water [nitric acid] will be produced perfectly.If you want to recover gold from silver, cut the alloy into pieces, place them in a fl ask, and seal it well. Then let the divine water [nitric acid] do its work and separate [fi lter] out the gold: you will get metal in powder form.

This chapter was inserted later (probably in the 13th cen-tury, see Ch 41). The nitric acid dissolves the silver out of the gold/silver alloy while gold remained as sediment. The decisive ingredient in this recipe is saltpetre, while the addition of sal-ammoniac is unusual. Otherwise, it was only utilised in combination with saltpetre and vit-riol or alum to make aqua regia; see Geber (XXII). Here, however, nitric acid is intended, since aqua regia would dissolve the gold. The time allowed is contradictory and the 65 hours are only understandable as a maximum. The following chapter indicates 24 hours. See Ch 41 and 43 about nitric acid.

43) ANOTHER COMPARABLE [RECIPE] [NITRIC ACID]. Take 2 pounds of alum, 1 pound of saltpetre, and 1½ pounds of Roman vitriol. Crush them, put them into a distillation vessel [alembic], seal this well, and place it on a stove. Connect [the distillation vessel] below to a [receiving] fl ask to collect the acid. In this manner, the divine water [nitric acid] will be produced in 24 hours.If you want to separate gold from silver, pour the acid into a glass [vessel] and place it into hot ashes: the silver will be dissolved and the water [aqua fortis] foams [as it] reacts with it. Now take the water [aqua fortis] that contains the [dissolved] silver and place it onto the stove in the distillation vessel [alembic]. Make a weak fi re and collect the distilled water at the nozzle; the silver [nitrate] remains on the bottom [of the alembic].

This chapter was inserted later (probably in the 13th century, see Ch 41–42). In the recovery process, silver is dissolved in nitric acid to form silver nitrate with a

‘foaming’ release of hydrogen. Following the separation of the solution from the gold (not mentioned here) that remained in the fi rst alembic as sediment, the water is distilled off from the silver solution in a second

alembic so that silver nitrate remains as sediment. See Ch 41–42.

44) REFINING OF GOLD [CUPELLATION WITH ANTIMONY TRISULFIDE]. Take 8 ounces of antimony [markazétan] and 4 ounces of sulphur, melt them to-gether in a crucible: antimony trisulphide [ántemónion] will form.If you want to refi ne granulated gold, place the gold into the middle of the fi re in a crucible. Then add as much antimony trisulphide as you want until it comes to a rolling boil. In order to achieve a [gradual] cooling, place the crucible into the dying fi re on a Greek tile until it is [completely] cooled.

This chapter was probably inserted later (in the 15th century) since the origin of this process is considered to be more recent (Berthelot and Ruelle 1888, II:319 footnote 2); see also Ch 41–43. Antimony and antimony trisulphide (stibnite, Sb

2 S

3) were often mistakenly inter-

changed terminologically and have a history of confused names. The context plainly shows that here ‘markazétan’ means antimony (see below, Dorn 1567), while antimony trisulphide is referred to as ‘ántemónion’ until well into the Middle Ages. By melting the unrefi ned gold with antimony trisulphide, two layers are formed in the cruci-ble [cupel]; the upper layer contains the foreign metals compounded with antimony, and the lower consists of

Figure 12: Detail from St Eloi in His Workshop by Niklaus Manuel, called Deutsch. Techniques: (left) raising a chalice on a T-stake; (top) engraving sheet silver cemented onto an engraver’s cushion; (right) pressure polishing (?) a ring. Tools and materials (L to R): (top) two forged silver ingots; (centre) borax can, compass, graver, triangular needle fi le; (bottom) raising hammer, canister for weights, rabbit’s foot as a brush for metal dust, soldering tongs, soldering dish with paillons, and a feather for applying solder. Products: (top) silver dish with a fi re-gilded sun, (bottom) sexfoil foot for a chalice. (See polishing Ch 26, 39a, 49; forging 4, 9, 10a, 33, 55; solder and soldering 9–11, 12, 24, 27, 32, 39a–b; borax 5, 8, 32, 33, 39a, 53; rabbit’s foot 26; feather 5, 28, 29, 39a; fi re–gilding 3, 26). [see also Plate 31]

84


the gold and antimony regulus. Not given here are the instructions to repeat the melting process two to three times and then to scorify the gold, whereby the antimony burns off. Even if this chapter was not inserted until 1478 by the last copyist, Pelecanos, it would still be the earliest description of this procedure. Using the term antimony for antimony trisulphide – which had been called stibium – is fi rst recorded in Salerno by Constantinus Africanus (Anon 1536, 381). Its cleansing power in relation to other metals is men-tioned in Paracelsus (sect I.10:362). The use of metallic antimony (called ‘marcasita [!] plumbea’ among other names) for refi ning gold is also described by Gerhard Dorn (1567,45; Libavius 1597, 212). See also Ch 1 and 45 about gold refi ning.

45) ANOTHER COMPARABLE [RECIPE] FOR SILVER [/GOLD ALLOY] [CUPELLATION WITH ANTIMONY TRISULFIDE]. Recover gold in powder form from silver and put the [gold] powder into a crucible [cupel]. Then mix it in the crucible with antimony trisulphide [ántemónion] and heat. Then place [the cupel] onto a Greek tile and let [it slowly] cool down; this way, you get fi ne gold.

This chapter was probably inserted later (in the 15th century, see Ch 44); see also Ch 41–43. Even if this chapter was inserted by the last copyist, Pelecanos, it would still be the earliest documentation of this pro-cedure. It utilises the method of cupellation described in Ch 44 with antimony trisulphide, for gold that was separated from silver by refi ning, and then it should have attained the highest grade of purity. See Ch 42–43 about recovery, and Ch 1 and 44 about refi ning.

46) IF SILVER OR GOLD ARE DEFECTIVE [BRITTLE] [MELTING WITH SUBLIMATED MERCURY?]. Put new [correct: sublimated?] quicksilver and brick dust into a crucible, heat it, and the metal will become more malleable. The more [of the additional ingredients] you add, the more beautiful the product will be.

By melting gold with mercuric chloride (HgCl2) the

base metal impurities that cause brittleness, such as iron, zinc, and tin, are converted into chlorides which vaporise along with the mercury, while the gold does not react chemically. Here, as in Ch 1, 2, 23 and 31, the added brick dust is intended to absorb the other substances released in the melting process (see Ch 31). First described here, this procedure for making gold malleable was utilised until modern times. Recipes are documented in Curiöser Künstler (I:105) and in Der Künstliche Gold- und Silber-Arbeiter (13/19 et

al). Sublimate, which releases poisonous vapours, was later replaced by anhydrous copper chloride (Eichler 1887, 48). An application of this procedure for silver is not known.

47) FIXATION OF QUICKSILVER [PALE GOLD-COLOURED ALLOY]. Take as much quicksilver as you like and the same amount of lead, and place them onto the stove in the shard of a vessel. Add some cannon [?] bronze [loympárdis] and an excellent pale gold[-coloured alloy] [ásemos] will form.

This chapter may be an insertion from the 14th century. The title refers only to the fi rst sentence in which the complicated process of fi xing or hardening mercury with lead is described in short form (Libavius 1597, 109). If the product is melted together with bronze, whereby the mercury evaporates, a leaded tin bronze of unknown proportions is the result. One example would be a bronze used for art casting consisting of 3.5–5% Sn, 18–23% Pb, and the rest copper. Without indicating the intended use, the Mappae Clavicula (89C/221A-B) contains three recipes for Cu/Sn/Pb alloys and mentions Brindisi as the origin in two cases. Recipe 89A describes a similar recipe including mercury, but omitting lead, that corre-sponds to a speculum alloy from Brindisi. In its style, our recipe is consistent with the surrogate gold recipes in the Greek papyri, however, these do not include an identi-cal alloy. The resemblance to the Mappae Clavicula is very close. The term ‘loympárdis’ (literally ‘metal of the Lombards’) was translated by Berthelot as ‘bronze à canon’. This would indicate a later reworking of the text, since there is no evidence of cannons in Europe before 1326 (in Florence). However, since the term ‘Lombards’ was used until the 13th century to mean Italians (Lexicon 2002, V: 2098), one could speak here of Italian bronze without having to consider a later dating. See Ch 48.

48) OTHER [RECIPE] [PALE GOLD-COLOURED ALLOY]. Put quicksilver together with onion juice as well as cannon [?] bronze [loympárdis] into a vessel and place it onto the stove. Take lard and warm it so that you will get a caustic solution [soap suds]. Pour this solution onto the pale gold [alloy] [ásemos] in the crucible, and gold-coloured metal will result.

This chapter may be an insertion from the 14th century. The alloy mentioned in the fi rst sentence is consistent with the one in the Mappae Clavicula (ch 89A); see Ch 47. About the cleansing action of warmed onion juice, see Ch 37. Soap is made by treating fat (lard) with an un-named alkali. See Ch 51 about soap making. See Ch 47 for the term ‘cannon bronze’.

85


49) ABOUT THE WAY TO MAKE GOLD[-COLOURED] LETTERS. Take gold-coloured bronze, crush it on a porphyry [slab], add some honey, and grind thoroughly. Then put it into a vessel and wash it well with water to remove the honey. Then prepare it with egg white and write. When [the letters are] dry, polish [them] with a pumice stone [correct: polishing stone] or wolf’s tooth and [the writing] will be beautiful. Squeeze the egg white through a sponge several times making the mass quite fl uid so that it will not thicken. Also add white, ground lead oxide. When the gold[-coloured bronze] adheres well, wash out the egg white in order to remove it.

The Greek papyri from around 300 AD and sources from the 9th century contain similar but not identical recipes. Writing with gold-coloured bronze was not de-scribed again until Theophilus (I.23–27). He mentions the polishing stone, as here in Ch 19. The production of lead oxide from lead and lead ore containing silver are described in the Compositiones (Z4–13/13–18). See Ch19 and 20a–b about gold writing.

50) ABOUT THE PROCESS FOR MAKING COPPER SHIMMER LIKE GOLD [GOLD–COLOURED ALLOY]. Take 1 ounce of evaporated toútia [zinc precipitate, tutty], in the same manner, [take] 1 ounce of excrement and 1 ounce of dried black fi gs, grind everything in a mortar and mix it. Prepare 1 ounce of tin, and after you have pounded it fl at, cut it into pieces. Mix [the copper and the rest of the ingredients] with this, put [everything] into a crucible; seal the top with clay, blow [with a bel-lows or blow pipe], and heat. When you think the metal might have started to melt, cover [the crucible] again and complete the melting [process]. Mix the ingredients anew and proceed as before, so that you use up every-thing; it [the alloy] will [appear to] be like gold.

Until the middle of the 18th century, brass was not made of the pure metals copper and zinc, but rather through cementation of copper with zinc ores. The easily-vola-tilised zinc precipitated in the cupola furnace as fi nely-granulated tutty, which consisted mainly of zinc oxide (ZnO); see Ch 56 for sources. In this impure form, zinc is alloyed here with metallic copper and tin to a Cu/Sn/Zn alloy with an unknown copper content. For example, an alloy consisting of 6.5% Sn, 3% Zn, and the rest copper has a golden colour. The organic additions named here carbonise; they fl oat on the surface of the molten metal, protecting it from oxygen, and have a reducing effect. Again, the Greek papyri and 9th-century sources contain similar but not identical recipes. In these sources, the earlier name cadmia (or kadmeía) was preferred for zinc ores, such as calamine (ZnCO

3) and tutty, while the

name toútia (tutia or tutie) appeared only under Arabian infl uence. These terms were not used consistently, but cadmia and calamine were more often used for zinc minerals and toútia more often for tutty.

51) ABOUT SOAP. First take the soap and rub [it to-gether] with salt. Then proceed [with the work].

As in Ch 48, the composition of the soap is not given. The Mappae Clavicula (ch 280) describes the production of a soap, which was also recommended for making a fl ux for soldering, from olive oil or tallow, wood ashes, lime, and salt. This composition would be roughly comparable to our incomplete recipe, while ch 288D in the same source describes a strong French soap made of tallow, oak ashes, and lime. Theophilus (III.51) describes soap making with beech wood ashes and pork fat in the context of colloid solder production, where the soap disintegrated in the heat, thereby releasing carbon which had a reducing effect.

52) ANOTHER [RECIPE] [COPPER PICKLE]. Take sal-ammoniac, salt, and water, [and] grind it well. Then use it to give a shine to copper.

Except for the addition of salt, this is the same pickle that is recommended for silver in Ch 16c (qv).

53) GLASS [VITRIFYING FLUX MIXTURE]. This is the vitrifying medium [fl ux] for soldering that does its work together with sal-ammoniac, alum, and salt.

Since neither sal-ammoniac, nor alum, nor table salt have a vitrifying effect, it is possible that borax was meant by ‘glass’ in the title. About borax, see Ch 9.

54a) ABOUT [THE PROCESS FOR] MAKING TIN WHITE. Take as much as you want of the lemon-yellow orpiment [kítrinon] from Pontus as well as the same amount of soda [salonítrion]; grind them well. Then mix [them]. After this, put them together with the previously named [Ch 53] fl ux onto a [char]coal fi re and heat until no more smoke escapes. The product will become as white as snow. After this, take [it off the fi re], crush [it] well, put 4 ounces of tin into the crucible, and add 1 ounce of opsiastiké. Set aside 6 parts [by weight]. As soon as the tin is in the middle of the crucible, scatter a fi rst portion [of the prepared mixture] onto it: cover with [char]coal and heat until smoke escapes. Now again take another portion just like the fi rst time and put it [into the cruci-ble]. After this, pour [the resultant product] into a small iron vessel and the work will be complete.

86


Arsenic trisulphide (As2S

3), which was originally

called arsenikon, was named orpiment as a mineral and appeared in combination with realgar; see Ch 12. According to the description given here, orpiment is mixed in the crucible with the fl ux mixture described in Ch 53, whereby it decomposes into white arsenic, ie ar-senic trioxide (As

2O

3) and sulphur dioxide that escapes

as a vapour. In the following smelting with tin and the unidentifi ed additive, opsiastiké (apparently a vegeta-ble product; see Ch 16a), under a covering of charcoal, the arsenic trioxide is reduced to metallic arsenic that compounds with the tin to make a white alloy. The white colouring effect of arsenic as an alloying constituent was fi rst mentioned by Stephanos Alexandrinos using the example of silver alloys. This is the fi rst description of this procedure for tin.

54b) [GIVING A GOLD COLORATION TO SILVER]. If you want to gild [give a golden colour to] silver, proceed as to your need and desire; toss [the product into the silver]. And when you have mixed the product with the silver, add some dregs [tartar] into the crucible; I mean: a quarter.

Since the ‘product’ is tossed into the crucible, it cannot refer to the preparation from Ch 54a. From parallels in other recipes (see below), it can be inferred that here realgar (see Ch 12) was probably meant by the

‘product’. The Leiden papyrus (ch 50) is the fi rst recipe for the gold coloration of silver with the aid of realgar, however with the addition of iron vitriol and cinnabar. In a similar manner the Mappae Clavicula (ch 72) describes the utilisation of a liquid preparation of iron vitriol, realgar, unidentifi ed elidrium, and gum resin, into which the heated silver is immersed. In all of these cases, surface coloration occurs through cementation. Our fusion process was possibly also originally based on a process for surface coloration.

55) ABOUT THE PROCESS FOR MAKING COPPER GOLD-LIKE [GOLD-COLOURED BRASS]. Take 3 parts tóutia [tutty, calamine], 1 part curcuma, 1 part raisins and dried red fi gs, honey, horse beans [broad beans?] … [omission by Berthelot and Ruelle 1888], 1 part inner skin of almonds, liquorice root, egg yolk, and saffron, as well as 1 part dried red ox-gall. Grind the tutty [or calamine] with oil, as you would pulverise cinnabar, and make a dough of it; then grind the rest of the ingredients and put them together. Take 3 ounces of copper, pound it on the anvil to thin sheets, coat it with the indicated substances, place it into a crucible, and seal it with refractory clay [ie the usual for luting], place it on the fi re, and blow energetically with the apparatus [bellows].

When the product has reached high heat, toss these [above-mentioned] substances onto it and the copper will become as beautiful as gold.

As in the recipe in Ch 50, here zinc in the form of tutty or calamine (smithsonite, ZnCO

3), with the addition of

a great deal of organic matter which carbonised and had a reducing effect, is melted together with the copper. Here, however, no tin is added. If the use of calamine is assumed, the result was a gold-coloured, forgeable and, if cooled slowly, very hard brass. According to stoichio-metric calculation, this indicates a composition of 60.5% Cu and 39.5% Zn with a melting temperature of around 886°C. Hardening during the cooling process can be prevented by annealing. The embellishment of copper by adding an ‘earth’ is fi rst mentioned in Theophrastus (VIII.49). No differentiation is made between the zinc minerals smithsonite (zinc carbonate) and hemimorphite (zinc silicate), nor is a detailed description given for the production of tutty in the form of zinc oxide (ZnO), until Pliny (XXXIV.2/4/100–105) and Dioscurides (V.74–75), who mention three different qualities. Alloying with copper is only mentioned incidentally, however. The Mappae Clavicula (ch 74) gives a description of brass production which is very close to our Ch 55 (with the exception of the organic substances not indicated there) including the emphasis on the golden colour. A detailed description of the production of brass is fi nally provided in Theophilus (III.64–66), which points out that only

Figure 13: Bezaleel and Aholiab making the holy vessels from a German Bible. Bezaleel is forging an ingot held with large tongs in his left hand, while Aholiab steadies the other end with small tongs. The parallel grooves caused by blows with the narrow hammer pane are visible on the ingot. In the left background, a fi re burns in the forge with a large bellows at its side. (See forging to sheet Ch 4, 9, 10a, 33, 55; bellows 55, 51). [see also Plate 33]

87


superior brass made with lead-free copper can be gilded. See Ch 35 about curcuma.

56) THE WATER OF THE INSURED METHOD. Take the clean and unblemished offspring of a living bird [ovum philosophicum] ....

Filled with allegoric terms and code names, this chap-ter is an alchemical text on the making of philosophers’ stone and the fraudulent production of gold by using a stirring rod with gold secreted in its lower end.

57) [ABOUT THE SAME DIVINE WATER]. Someone else says: take the amount of egg [ovum philosophicum?] that you want, let it boil, and after you have broken it, remove all the egg white....

This is an alchemical text written by Zosimos.

Acknowledgements and details of Figures

Special thanks are due to Ann Schadt and Harald Römer for their help in translating the German text (Wolters 2004) into English.

1: Panel painting formerly attributed to Taddeo Gaddi. It is Tuscan, from the second half of the 14th century, and is now in the Prado Museum, Madrid. Photo: André Held†, Ecublens (Switzerland).2: Paten from Lower Saxony, c1160/70 AD, diameter 235mm. Photo: Sculpture and Applied Art Collection, Kunsthistorisches Museum, Vienna (inv no 8924).3: Byzantine, 955–963 AD. 480mm by 340m. Photo: Domschatz und Diözesanmuseum, Limburg an der Lahn (inv no D3).4: Detail of etching by Etienne Delaune, Goldsmith’s Workshop I, Augsburg 1576. Photo: Graphische Sammlung, Staatsgalerie, Stuttgart (inv no A 61554).5 and 10: Details from etching by the Bileam-Master, St Eloi in his Workshop, c1460. Photo: Rijksprentenkabinet, Rijksmuseum, Amsterdam (inv no 1213).6: After Ortus Sanitatis (Mainz 1491) and A Schramm, Bilderschmuck der Frühdrucke, vol 15 (Leipzig 1932).7: Fresco, 1440–1446 AD, Chapel of San Vincenzo, Basilica of San Giovanni Battista, Monza. Photo: Museo del Duomo di Monza e Bibliotheca Capitolare.8: English?, 1170/80 AD, diameter 285mm. In the treasury of the Benedictine monastery, Kremsmünster. Photo: Stift Kremsmünster.9: Fresco, c70 AD, triclinium, Casa dei Vettii, Pompeii. Photo: author’s archives.11: Probably made in southern Russia under Byzantine/Oriental infl uence at the turn of the 13th/14th centuries.

Now in Chamber of Arms, Kremlin, Moscow. Photo: Vneshtorgizdat, Moscow.12: Oil and tempera on wood, 1515. Now in Kunstmuseum, Bern. Photo: André Held†, Ecublens (Switzerland).13: Coloured woodcut from the German Bible il-lustrating Exodus 30:1–10 and 35:30–36:7. Printed by Anton Koberger, Nuremberg, 1483. Identical with a woodcut in Bibles by Heinrich Quentell, Cologne, c1479. Private collection.

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The author

Jochem Wolters is now retired. He trained as a sil-versmith, visited the École des Beaux-Arts, Aix-en-Provence, and studied education, social sciences, and metallurgy at universities in Hamburg and elsewhere. He was Director of the Goldschmiedeschule at Pforzheim, 1983–2001. Since 1965 he has systematically col-lected and evaluated written sources on the history of goldsmithing techniques. He has published numerous articles and books on the historical development of these techniques: Zur Geschichte der Löttechnik 1975, Die Granulation 1983, Der Gold- und Silberschmied, Vol 1 Werkstoffe und Materialien 2000. He has contrib-uted to: Handbuch Europäische Technik im Mittelalter, Reallexikon zur Deutschen Kunstgeschichte, Reallexikon der Germanischen Altertumskunde, Lexikon des Mittelalters, etc. He is currently working on a history of all goldsmith techniques, materials and tools on the basis of written sources, discoveries during restoration, and historic relics.Address: 32 Rue des quatre vents, F-67630, Lauterbourg, France.e-mail: [email protected]

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