in every branch of art and science, we accordingly find in history, that though well supplied with rive2, many canals and aqueducts were constructed, or at least begun, in the days of her prosperity. And here it may not be out of place to offer as a conjecture, that canals were in many instances originally adapted to other purposes than those of commerce, and that this latter object was rather an adaption than an invention. Thus the canals, which Strabo informs us were cut in Beotia for drawing off and keeping at a certain level the waters of Lake Capois, were afterwards used for the purposes of commerce and formed a commodious line of navigation. A navigable communication between the Ionian Sea and the Archipelago was early attempted by the Greeks, who designed a line of canal across the Isthmus of Corinth, but failed in the execution.
Their rivals and, in most cases, successful imitators, the Romans, were equally alive to the advantages of inland navigation. No less than three of the Roman Emperors renewed the attempt of cutting a canal across the Isthmus, but were obliged to abandon the project.
Drusus, who commanded, under Augustus, an army which was to march into Germany, had a canal made from the river, now called the Rhine to the Issel, for the sole purpose of conveying his army upon it. By this canal he lessened the waters of the right branch of the Rhine, and in the course of his work formed a third mouth of that river into the sea, as is mentioned by Pliny, Lucius Verus, when the Roman Army under his command was in Gaul attempted a canal between the Moselle end the" Rhine; another canal twenty-three miles in length was made by the Romans in the reign of Claudius, between the Rhine and Maese, supposed to be the canal, which now commences at Leyden and passes by Delft to its junction with the Maese at Sluys. This is an instance of adoption, the canal being originally cut for the purpose of draining the country when overflowed by inundations from the sea, but subsequently applied to the purposes of navigation. The canal, which is still used for the purposes for which it was constructed, viz. that of draining Lake Celano, formerly the Fucine Lake, into the Liris, was executed by Claudius, who employedthirty thousand men thereon for no less a period than twelve years.