A History of Hindu Chemistry from the Earliest Times to the Middle of the Sixteenth Century A.D. v1.c20: Note on the Killing of Metals
A History of Hindu Chemistry from the Earliest Times to the Middle of the Sixteenth Century A.D. v1.c20
- Language
- English
Note on the Killing of Metals
v1.c20.1
From the time of the Charaka and the Susruta we find metallic preparations in the shape of oxides, sulphides and sometimes chlorides recommended for internal administration. The various formulas, which will be found scatttered throughout above, give us methods for killing the metals.³ But a *killed* metal is not necessarily a compound; it sometimes means a metal deprived of its well characterised physical properties, *e.g.* colour, lustre &c. Thus the Ayurvedic killed gold and silver often represent the respective metals in a fine state of division. Take for instance the following recipe from "Rasaratnākara" by Nityanātha :— "Rub gold leaf with 4 times its weight of *killed*
v1.c20.2
(1) Carbonate de potasse.
(2) Potasse caustique impure.
(3) See pp 30-31, 48 72-73.
v1.c20.3
mercury (i. e. sulphide of mercury) and sublime the mixture in a closed crucible. On repeating the process 8 times, the gold is killed." (Cf. also the processes described in pp. 105-106). In the preparation of "makaradhvaja" (p. 132, note) the gold, which is left behind, would be regarded in the same light. As the Hindu Iatro-chemists were very particular about the killing of the metals being ensured, they had often to hit upon proper tests for securing this purpose. Thus "Rasaratnākara" says:—"In order to examine whether the mercury has been completely reduced to ashes, it has to be heated over a gentle fire for 3 hours. If the weight remains constant, know then that it has been completely killed." In other words it means that if there be any free mercury present, it would volatilise off and thus there would be a loss in weight. In page 118 will also be found some tests for killed iron. The language of a portion of couplets 25-28 is somewhat obscure and the meaning seems to be the very reverse of what the context would suggest; "killed iron is that which, on being mixed with treacle......honey and heated, does not revert to the natural state." By "natural state" the author probably conveys the state in which it originally was.
v1.c20.4
i.e of an oxide, as immediately below he figuratively speaks of the resurrection of the dead (p. 120). Indeed, the ideas of the alchemists of the East and the West ran so closely on parallel lines that the best commentary we can offer to the above is the following extract from Hoefer's work, describing the notions current among the old Egyptinas.
v1.c20.5
*Expérience.* On brûle, on calcine du plomb ou tout autre métal (excepté l'or et l'argent) au contact de l'air. Le métal perd aussitôt ses propriétés caractéristiques, et se transforme en une substance pulvérulente, en une espèce de cendre ou de chaux. En reprenant ces cendres, qui sont, comme on disait le résultat de la mort du métal, et en les chauffant dans un creuset avec des grains de froment, on voit bientôt le métal renaître de ses cendres, et reprendre sa forme et ses propriétés premières.
v1.c20.6
*Conclusion :*—Le métal, que le feu détruit, est revivifié¹ par les grains de froment et par l'action de la chaleur. (T. 1. p. 228).
v1.c20.7
¹ Les mots revivifier, rivivification sont encore aujourd'-hui employés comme synonymes, de réduction de désoxydation.
v1.c20.8
"N'est-ce pas là opérer le miracle de la résurrection ?" T. 1. p. 228
v1.c20.9
Other "experiences" as well as technical terms have also their exact analogues in the language of the Western alchemists. Thus side by side with the "tests for killed mercury" (p. 74) and the "process for the fixation of mercury" (p. 131) we may quote:
v1.c20.10
"Viennent ensuite toutes sortes de recettes pour la "combustion" de l'argent, de l'or, du cuivre de l'étain, etc., faisant parfois double emploi avec le le livre II. Rappelons ici que le mot *combustion* signifiait la calcination des métaux en présence de diverses matières spécialement le soufre, le mercure, les sulfures métalliques, etc. Les produits en étaient dès lors fort multiples.—"La Chimie au moyen âge", I. p. 309.
v1.c20.11
"La calcination du mercure était appelée à cette époque coagulation ou fixation du métal." *Ibid*, p. 154.
v1.c20.12
The passage in Rasārnava describing the efficacy of the apparatus especially the line "without the use of herbs and drugs mercury can be killed with the aid of an apparatus alone" (p. 67.) is highly significant. It refers no doubt to the formation of the red oxide of mercury, the precipitate *per se*. Cf. "Il s'agit de la fabrication de l'oxyde de mercure préparé *per se*, c'est-à-dire sans addition d'aucun corps étranger." *Ibid*, p. 154
Linked texts (4)
- Carakasaṃhitā — Agniveśa (Āyurveda) & Caraka, Sanskrit
- Suśrutasaṃhitā — Suśruta & Nāgārjuna (siddha/alchemist), Sanskrit
- Rasaratnākara — Nityanātha Siddha, Sanskrit
- Rasārṇava — Sanskrit