d Ohio Canal, designed to connect the Mississippi
Valley with the Atlantic seaboard, fared much worse than the Erie Canal.
Less than two hundred miles have been completed, and practically no work
except that of repair has been done since 1850; the heavy grades between
Cumberland and Pittsburg render its completion improbable.

An excellent system of canals, the Ohio and Erie and the Miami and Erie,
connect the Ohio River with Lake Erie. These canals are in the State of
Ohio and aggregate about six hundred miles in length. They are important
as coal and ore carriers. Several hundred miles of canals were built
along the river-valleys of eastern Pennsylvania before 1840 for carrying
coal to tide-water. Most of them have been abandoned; one, the Delaware
& Hudson Canal Co., survives as a railway. Inasmuch as the coal went on
a down grade from the mines to the markets, it could be carried more
economically by railway than by canal.

Of far greater importance are the St. Marys Canal on the Canadian side,
and the St. Marys Falls Canal on the American side, of St. Marys River.
These canals obviate the falls in St. Marys River and form the
commercial outlet of Lake Superior. The tonnage of goods, mainly iron
ore and coal, is about one-half greater than that of the Suez Canal.
About twenty-five thousand vessels pass through these canals yearly.

The Chicago Ship and Sanitary Canal,[10] from Lake Michigan to Lockport,
on the Illinois River, was designed mainly to carry the sewage of
Chicago which, prior to the construction of the canal, was poured into
the lake through the Chicago River. The completion of the canal turned
the course of the river and caused the water to flow out of the lake,
carrying the city's sewage. It is intended to complete a navigable
water-way from Chicago to St. Louis deep enough for vessels drawing
fourteen feet. Its value is therefore strategic as well as industrial,
for by means of it gun-boats may readily pass from the Gulf of Mexico to
the Great Lakes.

Oceanic canals are designed both for naval strategic purposes and for
industrial uses. Thus, the Kaiser Wilhelm Canal, from the mouth of the
Elbe to Kiel Bay, across the base of Jutland, saves two days between
Hamburg and the Baltic ports. It also enables German war-vessels to
concentrate quickly in either the North or the Baltic Sea. The
Manchester Ship Canal makes Manchester a seaport and saves the cost of
trans-shipping freights by rail from Liver