A History of Hindu Chemistry from the Earliest Times to the Middle of the Sixteenth Century A.D. v1.c21.35

v1.c21.35

The processes of "Rasendrachintāmani" and "Bhāvaprakāsa" were also put to an experimental test, the globules of mercury were broken up by being rubbed continuously with a mixture of brick-dust, alum and common salt, and the mass was transferred to a stout bottle, which was wrapped in several folds of cloth, smeared with clay¹. The bottle was embedded in sand and heated for 3 hours²—vide illustration. The sublimate that was obtained was a mixture of calomel and mercuric chloride; in one experiment brick-dust was omitted and the product was pure calomel¹. There was necessarily some loss of mercury by volatilisation in these cases and the yield was short of the theoretical quantity. It will be seen that common salt, with alum or green vitriol, is quite competent to convert mercury into calomel; but the addition of brick-dust increases the chlorinating capacity, giving rise to a certain proportion of corrosive sublimate, which can probably be avoided by gentle heating as in the Japanese method.