To give a substantial idea of the _De Alchimia_ let us translate one of the formulae which it contains: ‘Medibibaz the Saracen of Africa used to change lead into gold [in the following manner]. Take lead and melt it thrice with caustic (‘comburenti’), red arsenic, sublimate of vitriol, sugar of alum, and with that red tuchia of India which is found on the shore of the Red Sea, and let the whole be again and again quenched in the juice of the _Portulaca marina_, the wild cucumber, a solution of sal ammoniac, and the urine of a young badger. Let all these ingredients then, when well mixed, be set on the fire, with the addition of some common salt, and well boiled until they be reduced to one-third of their original bulk, when you must proceed to distil them with care. Then take the marchasite of gold, prepared talc, roots of coral, some carcha-root, which is an herb very like the _Portulaca marina_; alum of cumae something red and saltish, Roman alum and vitriol, and let the latter be made red; sugar of alum, Cyprus earth, some of the red Barbary earth, for that gives a good colour; Cumaean earth of the red sort, African tuchia, which is a stone of variegated colours and being melted with copper changeth it into gold; Cumaean salt which is …; pure red arsenic, the blood of a ruddy man, red tartar, _gumma_ of Barbary, which is red and worketh wonders in this art; salt of Sardinia which is like …. Let all these be beaten together in a brazen mortar, then sifted finely and made into a paste with the above water. Dry this paste, and again rub it fine on the marble slab. Then take the lead you have prepared as directed above, and melt it together with the powder, adding some red alum and some more of the various salts. This alum is found about Aleppo (‘Alapia’), and in Armenia, and will give your metal a good colour. When you have so done you shall see the lead changed into the finest gold, as good as what comes from Arabia. This have I, Michael Scot, often put to the proof and ever found it to be true.’