_The Union Canal_, Pa., of which a section is shown on the next page, was commenced in 1811, and completed, after a long stoppage caused by the war of 1812, in 1832. The canal was intended to connect the Schuylkill and Susquehanna rivers. There is a lockage of 501 feet, with 88 lift-locks 3 guard-locks, and 2 weigh-locks, making 93 locks in all. The tonnage, which was 207,500 tons in 1858, fell to 29,800 tons in 1880. There were in the latter year 73 boats on the canal, averaging 100 tons. _The Schuylkill Navigation_ (see profile, p. 206) Pa., was incorporated in 1815, for the purpose of connecting the coal region of Mount Carbon with the city of Philadelphia. The canal was completed in 1826, when the depth of water was three feet, and the carrying capacity of the boats employed was 25 tons. By 1847 the minimum depth of water was made 6 feet, and the boats employed averaged 170 tons. In 1850, a flood, which devastated the Schuylkill valley, swept away dams, locks, tow-paths, and banks, so that hardly a trace of the canal existed for many miles, but this damage was subsequently repaired. The locks on the canal are 110 feet by 18 feet. The lockage on the main line of the canal is 618½ feet. There are 47 waterways, two overflows, with 3300 feet in both, 121 bridges, 22 culverts, 31 dams, and 12 aqueducts. The company has had a chequered career, and the canal was, in 1870, leased to the Pa. and Reading Railroad Co., for 999 years, at a yearly rental of 655,000 dollars. [Illustration: PROFILE OF THE PENNSYLVANIA CANAL.] _The Chesapeake and Ohio Canal_, illustrated in profile, is one of the most important works of its kind in the United States, connecting the Potomac and Ohio rivers, piercing the Allegheny mountains by a tunnel 3118 feet in length, and having cost, on its completion in 1851, no less than 11,071,000 dols., or 60,000 dols. (12,001_l._) per mile. The canal has a depth of 6 feet throughout. For about 60 miles it is 60 feet wide at the top, and 42 feet at the bottom; for 47 miles its surface width is 850 feet, and its bottom width, 32 feet; and for 77½ miles more the surface width is 54 feet, and the bottom width 38 feet. The locks are 100 feet long and 15 feet wide in the clear; they are capable of passing boats carrying 120 tons. There are 74 lift-locks and a tide-lock. The water-supply is drawn entirely from the Potomac, seven dams having been constructed across the river for this purpose. [Illustration: PROFILE OF THE ERIE CANAL, N.Y.] [Illustration: PROFILE OF THE OHIO CANAL.] [Illustration: PROFILE OF THE CHESAPEAKE & OHIO CANAL.]