Grand Harbor contains the naval hospital, arsenal, dock-yard, and custom-house, with Fort St. Angelo inside and Fort Ricasoli at the entrance. Quarantine Harbor has at its mouth Fort Tigné, while within is Fort Mangel and Lazaretto Island. The landing designed for the mail steamships is also here. The lazaretto is the most perfect of any arrangement of the kind in Europe. The tongue of land upon which the city stands is a narrow, rocky peninsula, dividing, as we have said, the two harbors, so that Fort Ricasoli at the entrance of Grand Harbor, Fort St. Elmo upon the point of the peninsula, and Fort Tigné at the mouth of Quarantine Harbor are all on a line at the sea front, and are capable of repelling the approach of any ship afloat. A bird's-eye view of the topography of the port of Valletta is at first a little confusing to a stranger, but its plan soon becomes clear, and the object of its arrangement is realized. It is then seen that the natural facilities have been admirably adapted to the general purpose by skilled engineers. We do not hesitate to say that there is not a more complete system of fortifications extant, in any part of the world, than the cordon of defensive structures at Malta. The forts of the harbor, however, form but a portion of the vast system of fortifications which completely surround Valletta. Such a gigantic amount of heavy stone-work as they represent could only be erected where the material was abundant and the labor cheap. The stone excavated in sinking the deep ditches was used in raising the escarps; and as to the necessary labor, that was done by the army of slaves retained on the island by the Knights. When they were not confined at the oars of the galleys, they were compelled to labor in erecting these elaborate defenses. Like the Egyptian builders of the Pyramids, the order was obliged to feed these workmen; but beyond that expense their services cost nothing.