early a century
earlier than in Italy locks were used in Holland where canals are very
numerous, owing to the favourable physical conditions. On the other
hand, the contrivance has been claimed for engineers of the Italian
school, and it is said that two brothers Domenico of Viterbo constructed
a lock-chamber enclosed by a pair of gates in 1481, and that in 1487
Leonardo da Vinci completed six locks uniting the canals of Milan. Be
that as it may, however, the introduction of locks in the 14th or 15th
century gave a new character to inland navigation and laid the basis of
its successful extension.

The Languedoc Canal (Canal du Midi) may be regarded as the pioneer of
the canals of modern Europe. Joining the Bay of Biscay and the
Mediterranean it is 148 m. long and rises 620 ft. above sea-level with
119 locks, its depth being about 6-1/2 ft. It was designed by Baron Paul
Riquet de Bonrepos (1604-1680) and was finished in 1681. With it and the
still earlier Briare canal (1605-1642) France began that policy of canal
construction which has provided her with over 3000 m. of canals, in
addition to over 4600 m. of navigable rivers. In Russia Peter the Great
undertook the construction of a system of canals about the beginning of
the 18th century, and in Sweden a canal with locks, connecting
Eskilstuna with Lake Malar, was finished in 1606. In England the oldest
artificial canal is the Foss Dyke, a relic of the Roman occupation. It
extends from Lincoln to the river Trent near Torksey (11 m.), and formed
a continuation of the Caer Dyke, also of Roman origin but now filled up,
which ran from Lincoln to Peterborough (40 m.). Camden in his
_Britannia_ says that the Foss Dyke was deepened and to some extent
rendered navigable in 1121. Little, however, was done in making canals
in Great Britain until the middle of the 18th century, though before
that date some progress had been made in rendering some of the larger
rivers navigable. In 1759 the duke of Bridgewater obtained powers to
construct a canal between Manchester and his collieries at Worsley, and
this work, of which James Brindley was the engineer, and which was
opened for traffic in 1761, was followed by a period of great activity
in canal construction, which, however, came to an end with the
introduction of railways. According to evidence given before the royal
commission on canals in 1906 the total mileage of existing canals in the
United Kingdom was 3901. In the United States