Note {2} — Chapter XXI

Note 2.—Tutty (i.e. Tutia) is in modern English an impure oxide of zinc, collected from the flues where brass is made; and this appears to be precisely what Polo describes, unless it be that in his account the production of tutia from an ore of zinc is represented as the object and not an accident of the process. What he says reads almost like a condensed translation of Galen’s account of Pompholyx and Spodos: “Pompholyx is produced in copper-smelting as Cadmia is; and it is also produced from Cadmia (carbonate of zinc) when put in the furnace, as is done (for instance) in Cyprus. The master of the works there, having no copper ready for smelting, ordered some pompholyx to be prepared from cadmia in my presence. Small pieces of cadmia were thrown into the fire in front of the copper-blast. The furnace top was covered, with no vent at the crown, and intercepted the soot of the roasted cadmia. This, when collected, constitutes Pompholyx, whilst that which falls on the hearth is called Spodos, a great deal of which is got in copper-smelting.” Pompholyx, he adds, is an ingredient in salves for eye discharges and pustules. (Galen, De Simpl. Medic., p. ix. in Latin ed., Venice, 1576.) Matthioli, after quoting this, says that Pompholyx was commonly known in the laboratories by the Arabic name of Tutia. I see that pure oxide of zinc is stated to form in modern practice a valuable eye-ointment.