Early Canals.—Among the earlier navigation works, perhaps the most remarkable was the canal which the Romans constructed for the drainage of Lake Fucino, illustrated on [p. 154.]
This canal, which was commenced by order of the Emperor Claudius, is said by Pliny to have occupied 30,000 men for ten years. The lake is surrounded by a high ridge of mountains called Celano, which are stated to be nearly fifty miles in circuit. The passage of the waters from the lake into the canal was witnessed by a vast number of persons, when the undertaking was completed, but the canal was not sufficiently deep to allow the water from the lower part of the lake to drain off, and although it was sought to correct this defect in Nero’s reign, the project was never really finished. As far as it went, the work is described by Tacitus,[94] while Virgil speaks of the lake—now no longer covered with water—as well known.[95]
Hydraulic engineering formed so important a part of the business of the ancient Romans that the pro-consuls were charged to lay before the emperors the best methods of changing the course of rivers, for the purpose of facilitating the approaches from the sea to the centres of the various provinces. Thus, we find that Lucius Verus, General of the Roman army in Gaul, undertook to unite the Saône and the Moselle by a canal. He is also said to have undertaken to connect the Mediterranean Sea and the German Ocean by means ofthe Rhone, the Saône and the Moselle, but the project was never completed. Emilius Scaevius, more successful, united the waters of the Po, near Placentia, for the purpose of draining the marshes round about. Other rivers in Italy were straightened, deepened, widened, or otherwise improved, while Rome was still “the mistress of the world.”
Canal on Lake Fucino.
SECTION THROUGH SIDE.
Some twelve centuries later the Italians were the canal makers of Europe. Alberto Pittentino, in 1188, converted the Mincio, from Mantua to the Po, into a canal, thus restoring it to the course from which the Romans had diverted it in the time of Quintus Curtius Hostilius.
The use of locks on canals may be said to date from this time. It is related that in the canalisation of the Mincio, Pittentino so regulated the rise and fall of the river that boats could ascend to Mantua and descend to Po, the depth being so equally maintained that the river was navigable for about twelve miles. This must have involved the employment of locks, however rude.[96]