History of Chemistry in Ancient and Medieval India, Incorporating the History of Hindu Chemistry by Acharya Prafulla Chandra Ray c37.s1.22

c37.s1.22

As we find from Ball's *Economic Geology of India*, the old indigenous process for the manufacture of alum survived even to the end of the 19th century A.D.. "Alum is principally used as a mordant in dyeing, but as a drug its employment is extensive in India. In two localities in Rajputana alum shales occur in quantities, from which alum was prepared. A small quantity was manufactured from slates obtained in the district of Sahabad in Bihar. Copperas or iron sulphate also occurs in the same region."