Ritual

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like gold, silver, zinc, copper, arsenic, were also used, as well as
various acids.
An important tantric treatise, Rasaratnakara, ascribed to
Nagarjuna (c. AD 800) is a repository of much chemical
information and many alchemical recipes. The text provides
valuable information about the various preparations of mercury,
including red crystalline sulphide of mercury, and techniques for
extracting mercury and zinc from zinc ore. It also describes more
than two dozen apparatuses for experiments in physico-chemical
processes. Another significant tantric treatise, Rasarnava (AD 1200)
has important information on chemistry and is a direct precursor
of iatrochemistry. An elaborate description of the location,
construction and equipment of chemical laboratories is available in
Rasaratna-samuccaya, an iatrochemical treatise of the 13 th century.
A later work, Rasasara (whose name literally means 'sea of
mercury'), is a purely chemical work and describes eighteen
mercurial processes.
Several special operations involving mercury and examples of
chemical composition and decomposition, by processes of
calcination, distillation, sublimation, steaming, fixation, and so on,
were elaborately discussed in the texts devoted to alchemy and
chemistry, as also were various metallurgical processes -
extraction, purification, killing, calcination, incineration, powdering,
solution, precipitation, rinsing or washing, drying, steaming,
melting, casting, filling. Here is a typical example of a recipe, for a
mercury potion, and the apparatus for reducing it to ashes:
Mercury is to be rubbed with its equal weight of gold and then [the
amalgam] further admixed with sulphur, borax, etc. The mixture is then
to be transferred to a crucible and its lid put on, and then submitted to
gentle roasting. By partaking of this elixir [i.e., the sublimate] the devotee
acquires a body not liable to decay. . . . [The apparatus, the Garbha-
Yantram, is described thus:] Make a clay crucible, 4 digits in length and 3
digits in width, with the mouth rounded. Take 20 parts of salt and one of
bedellium and pound them finely, adding water frequently; smear the
crucible with this mixture. Make a fire of paddy husks and apply gentle
heat.
One text speaks of 'killed mercury':
When the mercury assumes colours after having given up its fluidity, it is
known as 'swooned'. Killed mercury is that which does not show signs of
fluidity, mobility or lustre. When the quicksilver, which has acquired the
colour and the lustre of the rising sun, stands the test of fire [i.e., is not
readily volatilized], then it to be regarded as fixed. (Rasaratnakara of
Nagarjuna.)