6(3)

Geber’s furnaces, on the other hand, show a greater tendency
toward specificity when compared to those of the Rhases tradition : this
tendency becomes ever more pronounced during the culmination of the
Middle Ages. The specialization of furnaces did not so much produce new inventions as it did alterations - frequently of a radical nature - on
older types. The late Middle Ages witnessed the dispersion and perhaps
the earliest development, for example, of a specific genus of alchemical
oven - the covered, cylindrical « disgesting » furnace later called an
« athanor » [5] . The term « athanor » is derived, of course, from the Arabic at-tānnur, a bread baker’s oven - the Latin version came to mean a
specific furnace for low, constant heat, however, while its Arabic namesake was a high-temperature roasting oven, evolving from the ancient
glass-maker’s kiln (Ruska, 1937). Although the athanor and at-
tānnur
were both dome shaped, the former was highly insulated, in keeping with its goal of supplying constant heat. The need for such an oven
may have resulted from the increasing interest in amalgams allowed to
digest for long periods of time ; the 14th c. De multiplicatione of ps. Thomas Aquinas, for example, prescribes that an amalgam be heated twenty
six weeks in an athanor. This furnace receives a good description in the
appendix to John of Rupescissa’s L. lucis (the L. lucis is a fourteenth or
fifteenth c. text, but it is unclear to me wether the appendix formed part
of the original text - at any rate, the athanor’s description in the main
body of the text is consonant with the appendix). This furnus physicus
(fig. 4) is 3,5 feet tall, and 1,5 feet wide ; it has four sections and three
compartments. The lowest space, the ash-box, is 1 foot high, and separated from the focus by an iron grate. 9 fingers above the grate is an iron
plate, separating the vented focus from the hearth. The plate has a central, circular hole, 4 fingers wide. 3 iron slats (« A » in illustration), each
with a hole of different size, can be slid in from a slot in the furnace wall
to partially cover the central hole, thus varying the heat. A tripod fits over
the perforated slat, and upon this sits the ovum philosophicum (« B »), a
split globe 7 fingers in diameter, into which a « certain small clay vessel »
is packed to be heated. The illustration shows a conical, capped vessel
being heated in place of the egg. The hearth and its cover, which are luted inside and out for insulation, comprise 1 foot, 9 fingers in height ; the
center of the removable cover is bored so that the interior heat may be
judged.

IV. - Latin works depending on non-alchemical sources

The late 15th and early 16th c. saw the birth of two independent
genres which quickly outpaced the developments made in apparatus by
alchemists - the printed metallurgical treatise and distillation book. The
advances made in these texts were partially re-absorbed by the alchemists of the period, leading to a dependency which can be seen in the
Alchemia (1597) and Commentarii I (1606) of Andreas Libavius, one of
the great systematizers of Renaissance alchemy. The Commentarri I
gives pictures of over 189 furnaces, most of them drawn from purely metallurgical texts such as those of G. Agricola and L. Ercker. Libavius divides his furnaces into nine main types-athanors, reverberatory furnaces, assaying furnaces (fornaculae), baths (of water, ash, sand, or
steam), distilling furnaces (vesicariae, cacabariae), crucible furnaces,
descensories, « wind-ovens » (anemiae), and self-feeding furnaces (furni acesiae).

The fornax anemiae is not a blast furnace in the modern sense
(a shaft furnace where air is forced directly into the mixture of fuel and
ore), but rather an open hearth built outside, receiving the prevailing
wind, and equipped with built - in bellows : such a design is quite ancient.
The furnus acesiae, commonly known in the 15th c. as the piger Henricus,
had an attached, vertical, covered chute, in which one packed charcoal
or other fuel. The tube fed directly into the fire-box ; as fuel was consumed,
gravity would carry more down to replace it. Libavius’s Alchemia also describes numerous fornaces conjunctae, which employed a central tower-
oven to heat surrounding water-baths and the like. Libavius’s description of industrial cupellation- and muffel-furnaces were also culled from
the technical writers, especially Agricola. The same reliance occurs in
Libavius’s depiction of glassware ; his illustration of the caput Aethiopicum, for example, a stillhead enclosed in a glass, water-cooled unit, derives directly or indirectly from the L. de arte distillandi de compositis of H.
Brunschwig (1512), a medical work. In like manner, he includes high,
conical still-heads similar to the Rosenhut of Puff van Shrick’s nueczliche
materi von manigerley ausgeprânten wasser
(1478).

[1 This Liber de investigatione perfectionis magisterii is not the well-known work bearing the
same name, also attributed to Jābir ibn Hayyān (or « Geber » in Latin), and having the incipit « Investigatione(m) hujus nobilis (sime) scientie ex continua ... (TK 776). The latter
text has been printed many times, beginning with the incunabulum version of the Rome
printer Eucharius Silber (s.d. et l.) ; the former exists in manuscript only, though some parts
thereof are excerpted in Ruska (1935a) = [198-237).

[2 My rendition of Rhases’s notes on apparatus is derived entirely from Ruska (1935a) = [198-202).

[3 Gebri ... Summa perfectionis magisterii in sua natura ... , in Manget, J. J., Bibliotheca chemica
curiosa
, Genevae, 1702, vol. l. This is a reprint with slight variations of the
edition published by Marcellus Silber, and edited by Fausto Sabeo et al., between 1523
and 1527 in Rome. I am presently working on a critical edition of the Summa, but until this
task is accomplished, the reader may be advised to rely on the Sabeo edition and its reprints over the other available versions.

[4 The Liber fornacum, or Liber de fornacibus construendis has only been edited once, as is
also the case with the Liber de inventione perfectionis attributed to Geber. These works
were edited by a pseudonymous « Chrysogonus Polydorus »,and first printed in the ln hoc
volumine de alchemia continentur haec
... , (Nuremberg, 1541), printed by Johannes Petreius - the printer of Copernicus’s De revolutionibus orbium caelestium. Because of the
extreme rarity of this edition and its reprints, I have been forced to use a modern German
translation - Ernst Darmstaedter, Die Alchemie des Geber (Berlin, 1922). The L. fornacum
occupies pp. 114-125 of this version.

[5 The L. fornacum (Darmstaedter, op. cit., 116) calls the fixatory furnace an athanor. If the
L. fornacum is really by the author of the 13th c. Summa perfectionis, we may then see an
early, transitional usage of the term « athanor, we may then see an
early, transitional usage of the term « athanor » here, which is similar to the Arabic tannūr
in that it relates to a high temperature oven. By the 14th c., however, such texts as the
L. de multiplicatione and the L. lucis had restricted the term « athanor » to the low temperature version of the domed furnace.

[6 Archives de l’Administration des Mines et fonds Warocqué (Musée de Mariemont).

[7 Une fois pour toutes, signalons que nous utilisons le terme « histoire des sciences » pour
faire court. Nous préfèrerions le terme, plus adéquat pour désigner notre discipline : « histoire et philosophie de la science et de la technologie ». Il y a encore des historiens qui ne
savent pas que l’histoire ne trouve la justification de son labeur érudit que si elle débouche
sur les problèmes éternels de la philosophie (l’histoire n’est-elle pas encore, pour certains, un genre littéraire ?). Et il y a encore des historiens des sciences qui ne savent pas
que l’étude de l’évolution de la science est impossible sans prendre en compte l’évolution
technologique ...

[8 Il existe un establishment scientifique et industriel comme il existe un establishment littéraire et culturel. La culture, en effet, est aux lettres ce que l’industrie est à la science,
à la fois source et réceptacle. L’écrivain produit des idées qui seront transposées, modulées et diffusées par la culture, comme le scientifique découvre des faits qui alimenteront
l’innovation technologique, moteur de l’industrie. L’ingénieur industriel transpose les
connaissances scientifiques dans le monde de la production en grandes séries, comme
le cinéaste, le journaliste et le réalisateur TV, véritables ingénieurs culturels, transposent
la création littéraire dans le monde de l’imaginaire quotidien, celui du chaud biznesse et
des masse-médiats.



















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