LAKE FUCINUS.—ACCIDENT.

457

the melting of the snow on the surrounding Appenninescarry a large body of water, hut no stream goes out from it,and the evaporation is not sufficient to prevent the annualincrease of the waters, and the loss of most valuable land.In order to remedy this evil, the Emperor Claudiusemployed an architect named Apollonius, (if I rememberrightly) who constructed a tunnel through an elevated pieceof land that separates the plain of the lake from the riverLiri, or rather a tributary to it. It was expected that atleast eighty square miles of the most valuable land in Italy would be retrieved from the waters. The tunnel beingcompleted, and lined with brick, like that under the Thames,a day was fixed for letting out the waters. An immensescaffolding with splendid seats and awnings as at anamphitheatre was prepared for the Emperor and manythousand persons to witness the operation; and thiserection was placed just over the commencement of thetunnel, where the waters would be seen to rush from thelake. A similar construction was placed at the other endof the tunnel where the mighty rush would be seen to enterthe river Liri. But, unfortunately, the engineer was un-acquainted with the elastic properties of air;—he had notprovided for the escape of the vast column of it, which,pressed by the advancing water, should have been allowedto escape by vertical shafts entering the tunnel from aboveat frequent intervals along its course. We all, now a days,know that air forced into one end of a long tube will notmove beyond a certain distance, but just as it occurs indriving wool into a gun barrel, it will stick in the middle,and all the power applied to urge it onwards will tend toburst the channel. So was it on this fatal day of Imperialexhibition. The flood gates were opened,—the watersrushed into and filled the section of the tunnel, the airwithin it, pressed forwards by the waters, refused to progress