The church of St. Philippo Negri deserves a visit. It is a lofty oval hall. The altar is in a deep recess, and two narrow galleries run round it at a considerable height. In this church, in a back street of an out-post almost cut off from Spain, some unknown and self-designated politicians wove, in 1812, out of the threads of the philosophy of France, a tissue which was to clothe the nakedness of Spain, and to regenerate her. At that moment she was engaged in a desperate war with France. By those very doctrines her despot trampled on the liberties of France, and then converted her into the slavish instrument of his evil passions and lawless purposes against Spain. Up to the time when this constitution was proclaimed, faction, which had divided and distracted, for a century and a half, the other countries of Europe, had still in Spain been unknown. St. Philippo is thus a spot associated with greatness--but greatness of an easy kind. It is easier to kill a camel than--sometimes--to catch a flea. Cadiz, Oct. 26th. I made an excursion yesterday, in a Calesa, to the mainland, or rather, to the Isla St. Leon, which adjoins it. After travelling about four miles along the narrow ridge of sand that joins Cadiz to the main, you turn to the left, round the bottom of the bay, and enter on the salt pans, which extend throughout the Isla. There were ditches, tanks, and reservoirs, cut out in all shapes and dimensions. Heaps of salt were scattered about like pyramids; some, twenty feet high. I expected to obtain data respecting the evaporation of the Mediterranean, but was disappointed: neither is the water allowed to deposit in one place, nor are there successive fillings of water into the same basin before the salt is made. In either case, the rate of evaporation would have been furnished exactly; but the water passes through successive pans, becoming more and more charged as it advances to the inner tanks, where the crystallization is ultimately effected,--a process even then attended with difficulty.[74] There are, in the Isla, twelve government and seventy-two private works; the produce of the first is 12,000, of the other, 40,000 lasts. The cost is six quarts the Fanega; it is sold at fifty-two reals. The salt made at the private works is for exportation, and is taken off by the English, Americans, and French. These and the other salt-works of Galicia, the Asturias, &c., are farmed for 12,000,000 reals, by a singular adventurer of the court and the exchange,--M. Salamanca.