History of Technology in India, Vol. I: From Antiquity to c. 1200 A.D. v1.c18.s1.t4.25

v1.c18.s1.t4.25

As regards mercury and its compounds it may be said that mercury and mercurial compounds are not commonly referred to in this text, only at one place Nigrahīta rasa prayoga is found mentioned for internal use but it is also doubtful and at one place Rasottama term (may be denoting mercury) is found referred to in a paste yoga for external use. Hence it may be said that in the period of Caraka Saṃhitā mercury is found used for external application only. Further it may be pointed out that this external use of mercury is also found mentioned in the portion redacted by Drdhavala. Thus in this period of caraka the metals are used either in powder form converted to a very fine state of sub- division by heating the metals to red hot and quenching these into cold liquids (decoctions/juices/alkaline liquids) several times and then powdering finely. These metals are also used in solution form by putting iron powder into the liquids of Āsava and Āriṣṭha preparations and keeping it into the contact of liquid through the process (3-4 months) or till its complete dissolution. These (metals) are also used through oily media and sugar base mixed with lehya preparations, and also as paste after rubbing on stone.