320 WATER STORAGE AND CANALIZATION. 
professional opinion against the plan of his engineer, the Duke 
fortunately followed it, and his confidence was fully justified by 
its successful completion. The length of this canal is 29 miles, 
and in its course it traverses a very difficult country. 
Tn Scotland, the Caledonian and Forth and-Clyde Canals have 
proved highly advantageous to internal traffic, and have served to 
sh e coasting traffic in stormy seas for several hundred 
miles. The first, surveyed by James Watt in 1773, has a total 
length of 604 miles, which includes 37} miles of lake navigation, 
and connects Inverness on the east coast with Loch Eil on the 
west coast. Its summit level at Laggan is 102 feet above sea- 
Some few years ago it was proved on this canal that it was 
s 
The two principal Irish canals, called the Grand and the Royal, 
are noted more on account of their enormous cost than for the eng 
neering skill exhibited in their design and construction. TheG d 
anal connects Dublin with Limerick, has a total length of 164 
miles, including its branches ; it is 40 feet wide, 6 feet deep, and 
its summit level is 164 miles above the sea; its cost was 
cost was over £1,500,000. 
In Canada the English Government have constructed form 
purposes the Rideau Canal connecting Lake Ontario ey al 
river St. Lawrence through the Ottawa, and the Welland Can 
uniting Lakes Erie and Ontario. d 
The Americans have exhibited the same restless seep ® 
undertakings. The a te len of the 
6,000 miles, more Re nce of 2 N is confined to t 
States of New York, Ohio, and Pennsylvania. The Erie ais : 
which unites Lake Erie with the Hudson River, is 363 miles si 
70 feet wide at surface level, 42 feet at bottom, 7 feet pages 
its summit level is 292 feet above the sea. Its cost was ® ly 
£5,000,000 sterling. In the State of California irrigation is ech 
rted to, on account of the small average all, Ge 's 
surprising profit. According to the State Surveyor * ditches 
statistics for 1871, California could boast of 915 irrigalPS 
