Page:A History of Hindu Chemistry Vol 1.djvu/196

46 Another recipe includes alum-earth, red-ochre, sulphate of copper, yellowish (basic) sulphate of iron, rock-salt, orpiment and realgar.

Thin leaves of cast iron are to be smeared with the levigated powder of "the salt" and heated in the fire of the cow-dung cakes and then plunged into a decoction of the myrobalans and asafœtida. This process is to be repeated 16 times. The leaves are then to be ignited in the fire of the wood of mimosa catechu and afterwards finely powdered and passed through linen of fine texture.

The above process is equally applicable to the roasting of the other metals.

The origin of bitumen is much the same as in the Charaka and the Bower Ms.; the only difference