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A History of Hindu Chemistry from the Earliest Times to the Middle of the Sixteenth Century A.D. v1.c16.s3: Mineral Acids

A History of Hindu Chemistry from the Earliest Times to the Middle of the Sixteenth Century A.D. v1.c16.s3

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English

Mineral Acids

v1.c16.s3.1

Geber was up till recently credited with being the discoverer of nitric acid, aqua regia, silver nitrate &c. A careful examination of the works of Geber, both real and pretended, notably of the celebrated *Summa perfectionis magisterii*, has convinced M. Berthelot that the knowledge of the mineral acids was unknown not only to the Arabs but also to the European alchemists of the thirteenth century. It was a Latin author of the latter half of the 13th century who wrote the above memorable work and assumed the

v1.c16.s3.2

"Most of the saltpeter which is sold in *Guzuratta* comes from Ajmer, sixty Leagues from Agra, and they get it out of Land that hath lain long fallow. The blackest and fattest ground yields most of it, though other Lands afford some, and it is made thus : they make certain trenches which they fill with their Saltpetrous Earth, and let into them small Rivulets, as much water as will serve for its soaking, which may be the more effectually done, they make use of their feet, treading it till it becomes a Broath. When the Water hath drawn out all the salt-peter which was in the Earth, they take the clearest part of it, and dispose it into another Trench, where it grows thick, and then they boil it like salt, continually scumming it, and then they put it into earthen pots, wherein the remainder of the Dregs goes to the bottom ; and when the water begins to thicken, they take it out of these pots, to set it a-drying in the sun, where it grows hard, and is reduced into that form wherein it is brought into *Europe*." pp. 66-67.

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venerable name of Geber to gain public confidence.¹ Such instances of literary forgery are by no means uncommon in the alchemical literature of the East and the West.

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¹ "L'hypothèse la plus vraisemblable à mes yeux, c'est qu'un auteur latin, resté inconnu, a écrit ce livre dans la seconde moitié du XIIIe. siècle, et l'a mis sous le patronage du nom vénéré de Géber." "La Chimie au moyen âge," I. 349.

v1.c16.s3.5

The distillation of alum is referred to in Rasārnava and of green vitriol in R.R.S. (see pp. 71, 92) We have, however, no evidence that the acid thus derived was ever used as a solvent. Hoefer justly remarks that real progress in chemistry was impossible in India and China, as the preparation of mineral acids was unknown in both these countries.² At the same time we should remember that Rasārnava and similar other works lay stress upon vida, in which aqua regia may be said to be potentially present and which is fitly described as capable of "killing all the metals" (see p. 72)

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² "Hist. de la Chimie," T. I. p. 25, ed. 1866.

v1.c16.s3.7

The preparation of mineral acids is incidentally described in several exclusively medical works, composed probably in the 16th and 17th centuries, e. g. "Rasakaumudī" by Mādhava, Rasaratnapradīpa, and "Bhaishajyaratnāvalī" by Govindadāsa, &c. In the last work under the heading of mahādrāvakarasa, directions are given for distilling a mixture of, among other things, alum, green vitriol, salammoniac saltpetre and borax in a glass retort. In this way a dilute solution of nitro-muriatic acid is obtained, which is prescribed in derangement of liver and spleen. We have a similar recipe in which in addition to the above ingredients, rock-salt and sea-salt are used, thus yielding what is called “samkhadrāvaka” (lit. solvent for conch-shell.)

v1.c16.s3.8

The term “drāvaka” (solvent) seems to have been expressly coined to do duty for the mineral acids. We have seen all along that in the older works drāvaka was used invariably in the sense of solvent or flux (see p. 130) but never in the sense of a mineral acid, the knowledge of which seems to have spread both in the East and the West almost simultaneously. The regular application of the mineral acids to technical operations dates from the time of the Emperor Akbar or perhaps a little earlier. Thus in the *A'in-i-A'kbari* under the “Method of Refining Silver” mention is made of the use of *rasi* (aqua fortis). It is not easy to make out how much of the processes of the assay of gold and silver as described in the *A'in* is of Hindu origin.

v1.c16.s3.9

Royle, Sir W. O'Shaughnessy (“Manual of Chemistry’), Ainslie and others maintained that the Hindus were acquainted with the methods of preparing the mineral acids. These authors who wrote more than half-a-century ago derived their information at second-hand as none of them had probably read the Sankrit works in the original. Ainslie gives the following recipes as used in Southern India among the Tamil physicians for the preparation of sulphuric, nitric and muriatic acids respectively:

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Sulphuric acid: “The Tamil physicians prepared their article nearly in the same way that we do, *viz.*, by burning sulphur with a small with a small piece of nitre in strong earthen vessels.”

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O’Shaughnessy says: “sulphuric acid, the *Gun-dak ká áttar* of the Hindus has long been known among the Eastern nations. In southern India it has been prepared for many centuries.”

v1.c16.s3.12

Nitric acid: This acid the Hindus make a clumsy attempt at preparing in the following manner which must not be rigidly criticised by the chemists of Europe.

v1.c16.s3.13

Take of saltpetre . . . 20 parts. ,, alum . . . 16 ,, ,, the acid liquid from the leaves and stem of the Bengal horsegram . . . 18 ,, Mix and distil with an increasing heat till the whole of the acid is condensed in a receiver. Muriatic acid : "Take of common salt ,, 8 parts alum ,, 6 parts The acid liquid from the horse gram and distil &c."

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The very name of sulphuric acid, *Gundak ká áttar* is Urdu *i.e.* the hybird *lingua franca*, an admixture of Hindi with Persian. *Attar* in Persian means the volatile princinple, often odoriferous, *e.g.* *Guláb ká áttar* *i.e.* otto de Rose. "Gundhak" in Sanskrit is the equivalent for sulphur.

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