A History of Hindu Chemistry from the Earliest Times to the Middle of the Sixteenth Century A.D. v1.c21.17

v1.c21.17

The Chinese and Hindu methods¹ are essentially the same as in both alum plays an important part in that it yields sulphuric acid. Professor Divers in his explanation of the Japanese method supports the view that the hydrochloric acid at first liberated undergoes aerial oxidation, thus: 2HCl + O = H₂O + Cl₂; and it is the chlorine thus set free, which attacks the mercury, forming calomel—a view which has been accepted by no less an authority than Mendeléeff.² The author has all along entertained doubts as to the correctness of Divers' hypothesis and he has, in his lectures, pointed out to his students that some "catalytic agent" as in Deacon's process must account for the reaction involved. This now turns out to be so. It is the *ferric*