grammar and history; but, being fond of travelling, he resided some time at Constantinople, and acquired much wealth by dyeing cloth made in Italy, which was transported thither and committed to his care, on account of the abundance of alum in that neighborhood. Having by these means an opportunity of seeing daily the manner in which alum was made, and from what stones or earth it was extracted, he soon learned the art. When, by the will of God, that city was taken and plundered about the year 1453, by Mahomet II., Emperor of the Turks, he lost his whole property; but, happy to have escaped the fire and sword of these cruel people, he returned to Italy, after the assumption of Pius II., to whom he was related, and from whom he obtained, as an indemnification for his losses, the office of Commissary-General over all the revenues of the Apostolic Chamber, both within and without the city. While in this situation he was traversing all the hills and mountains, searching the bowels of the earth, leaving no stone or clod unexplored, he at length found some alum-stone in the neighborhood of Tolfa. Old Tolfa is a town belonging to two brothers, subjects of the Church of Rome, and situated at a small distance from Civita Vecchia. Here there are high mountains, retiring inland from the sea, which abound with wood and water. While Castro was examining these, he observed that the grass had a new appearance. Being struck with wonder, and inquiring into the cause, he found that the mountains of Asia, which enrich the Turkish treasury by their alum, were covered with grass of the like kind. Perceiving several white stones, which seemed to be minerals, he bit some of them, and found that they had a saltish taste. This induced him to make some experiments by calcining them, and he at length obtained alum. He repaired therefore to the Pontiff, and addressing him said, "I announce to you a victory over the Turk. He draws yearly from the Christians above three hundred thousand pieces of gold, paid to him for the alum with which we dye wool different colors, because none is found here but a little at the island of Hiscla, formerly called Aenaria, near Puteoli, and in the cave of Vulcan at Lipari, which, being formerly exhausted by the Romans, is now almost destitute of that substance. I have, however, found seven hills so abundant in it, that they would be almost sufficient to supply seven worlds. If you will send for workmen, and cause furnaces to be constructed, and the stones to be calcined, you may furnish alum to all Europe; and that gain which the Turk used to acquire by this article being thrown into your hands will be to him a double loss. Wood and water are both plenty, and you have in the neighborhood the port of Civita Vecchia, where vessels bound to the West may be loaded. You can now make war against the Turk: this mineral will supply you with the sinews of war, that is money, and at the same time deprive the Turk of them." These words of