The Positive Sciences of the Ancient Hindus c4.s2.27

c4.s2.27

*Chemical Compositions and Decompositions—Metallurgic Processes.*—In these writings¹ we frequently come across instances of chemical composition and decomposition by processes, more or less crude, of calcination, distillation, sublimation, steaming, fixation, etc. (भस्मीकरण, अधःपातन, उर्द्धपातन, स्वेदन, स्तम्भन, etc.), *e.g.* the preparation of perchloride of mercury by taking common salt and mercury (रसकर्पूर—पारदस्य श्‍वेतभस्मीकरणे चन्द्रिकाकारः); of sulphide of mercury (हिङ्गुल) by taking sulphur and mercury; of Sindúra from lead (सिन्दूरं नागसम्भवम्—Amarakosha, sixth century A.D.); of the medicinal compounds Svarnasindúra and Rasasindúra with mercury, sulphur, and gold, where gold may have been fancied to influence the resulting compound in some mysterious way, either as a "dynamic" or as a catalytic; also the extraction by chemical decomposition of mercury from sulphide of mercury (हिङ्गुल); of copper from sulphate of copper (तुत्थ, सस्यक) by heating this substance with one-fourth of its weight of borax (Rasaratna-samuchchaya,—*cf.* Bhávaprakása, तुत्थं तु ताम्रोपधातु किञ्चित् ताम्रेण तद्भवति); of zinc (यशद, जसद्) from calamine (रसक); of copper from pyrites (माक्षिक, विमल), etc. (though the golden pyrites were supposed to be a semi-metal of gold, containing some gold along with the essence of copper); the purification of mercury by repeated distillation from lead and tin with which it was wont to be adulterated in the market. The various metallurgic processes described are—extraction, purification, killing (formation of oxides, chlorides, and oxy-chlorides for the most part), calcination, incineration, powdering, solution, distillation, precipitation, rinsing (or washing), drying, steaming, melting, casting, filing, etc., to all which each of the known minerals was successfully subjected by the use of apparatus and reagents and the application of heat in different measures (खरपाक, मध्यमपाक, and मृदुपाक)—methods which, if often crude, especially from the absence of independent and isolated mineral acids, were yet in several instances remarkably simple and effective, and which, after all, by the use of various Vidas potentially containing mineral acids (aqua regia, sulphuric acid, hydrochloric acid, etc.), virtually accomplished the practical ends kept in view. To these were added several special processes for mercury (*e.g.* fixation), bringing up the number of mercurial operations to nineteen.