All these volcanic lakes are of considerable depths, whilst the lakes in the calcareous regions are shallow.[89] One amongst them, that of Fucino, has been drained recently, and the same fate is in store for that of Trasimeno. Lake Fucino originally occupied an area of 104 square miles, and its surplus waters discharged themselves towards the north-west into the Salto, a tributary of the Tiber. At an epoch not known to us the dimensions of the lake became less. It no longer discharged an effluent, but its waters rose and fell according to whether the seasons were wet or dry. Occasionally they rose as much as 50 feet, and two cities, Marruvium and Pinna, are said to have been swallowed up during one of these floods. At other times it was reduced to a swamp. The ancient Romans, desirous of suppressing a hotbed of fever, and of gaining fertile soil for agriculture, attempted to drain this lake. Claudius employed 30,000 slaves for eleven years in cutting a passage through the mountains from it to the Liri. This great work was carried on under the direction of the greedy Narcissus, but it turned out a failure, for after a short time the tunnel became choked. In the thirteenth century an attempt was made to reopen this tunnel, but the drainage of the lake has only been achieved quite recently, in accordance with plans designed by M. de Montricher, and carried out at the expense of Prince Torlonia. Between {263} 1855 and 1869 a new tunnel was excavated on the site of the ancient one, and nearly 150,000,000 cubic yards of water were conveyed through it into the Liri, and thence to the sea. The whole of the ancient lake bed has been converted into smiling fields, traversed in all directions by carriage roads; houses have been erected on spots formerly covered with water; fruit and ornamental trees have been planted; and the salubrity of the country leaves nothing to be desired now. Some idea of the progress made in the art of engineering since the time of the Romans may be formed by comparing this new tunnel with the old one. The latter was 18,500 feet in length, had an average section of 12 square yards, and cost (according to M. Rotrou) £9,840,000. The new tunnel has a length of 20,680 feet, a section of 24 square yards, and cost £1,200,000. [Illustration: Fig. 92.—THE ANCIENT LAKE OF FUCINO. Scale 1 : 412,000.] The Lake of Perugia, better known as the Lake of Trasimeno, on account of the terrible memories which attach to it, still retains nearly the dimensions which it had at the dawn of history. If this lake were to rise only a few feet, its surplus waters would find their way into the Tresa, a tributary of the Tiber; but its basin is shallow, and evaporation suffices for carrying off the water conveyed into it by its tributary rivulets. Amongst these is the famous Sanguinetto, on the banks of which the armies of Hannibal and Flaminius were engaged in battle, when, “beneath the fray, An earthquake reeled unheededly away.”