The position of Chicago at the southwestern extremity of Lake
Michigan, with prairies of the greatest fertility stretching hundreds
of miles south and west, makes the city the primary food-gatherer and
supply-distributor of the great Northwest, and this has been the chief
cause of its growth. In September, 1833, the Pottawatomies agreed to
sell their prairie homes to the United States and migrate to
reservations farther West, and seven thousand of them assembled in
grand council at Chicago, and sold the Government twenty millions of
acres of these prairies around Lake Michigan, in Indiana, Illinois and
Michigan, for $1,100,000. Thus was this fertile domain opened to
settlement. In the Indian dialect, Michigan means the "great water,"
and it is the largest lake within the United States, being three
hundred and twenty miles long and seventy broad, and having an average
depth of one thousand feet, with the surface elevated five hundred and
seventy-eight feet above the ocean level. On the Chicago side this
extensive lake has but a narrow watershed, the Illinois River,
draining the region to the westward, being formed only sixty-five
miles southwest of the lake by the junction of the Kankakee and
Desplaines Rivers. This narrow and very low watershed, considered in
connection with the enormous capacity of the Illinois River valley,
which is at a much lower level and appears as if worn by a mighty
current in former times, is regarded by geologists as an evidence of
the probability that the Lake Michigan waters may in past ages have
found their way to that outlet and flowed through the Illinois and
Mississippi Rivers to the Gulf. The diminutive bayou of the Chicago
River, with its two short and tortuous branches, made Chicago the
leading lake port, and thus brought trade, so that early in the race
it far outstripped all its Western rivals. Every railroad of
prominence sought an outlet or a feeder at Chicago, and the title of a
"trunk line" was adopted for a line of rails between Chicago and the
seaboard. The surrounding prairie for miles is crossed in all
directions by railways, and a large part of the city and suburbs is
made up of huge stations, car-yards, elevators, storehouses and
cattle-pens, almost overwhelming visitors with the prodigious scale of
their elaborate perplexity. The maze of railways and streets on the
level surface, all crossing at grade, as it has spread over miles of
prairie and grown into such enormous proportions, presents a most
serious problem, with which the city and the railways are now dealing
on a comprehensive plan, by which it is hoped that before long the
grade-crossings will be eliminated.
Another problem, found even more serious as the city grew, was the
drainage. In former years the sewage was discharged into the Chicago
River and Lake Michigan. The river became a most malodorous stream in
consequence, and as it had practically no descent, the current would
scarcely flow, and the lake, from which the city water-supply was
drawn, was more and more polluted. With the customary enterprise of
these wonderful people, however, they decided to make the only change
feasible, which was to take advantage of the descending watershed
towards Desplaines River and change their sewerage system so that it
would all discharge in that direction. The problem was solved by the
construction of the most expensive drainage works in the world, and a
complete change of the sewers, at a cost altogether approximating
$40,000,000. St. Louis and the towns along the Desplaines fought the
scheme, and there was protracted litigation, but the very existence of
Chicago depended on the result. The great drainage canal was completed
connecting the Chicago River South Branch with Desplaines River at
Lockport, twenty-eight miles southwest, where it discharges the
outflow from Lake Michigan, which then flows past Joliet, and
ultimately into Illinois River. This huge canal, opened in January,
1900, reverses the flow of the Chicago River, which now draws in about
three hundred thousand cubic feet of water per minute from Lake
Michigan and flushes the canal, which is also to be made available for
shipping. Thus the Chicago River flows towards its source with a free
current, and Lake Michigan has been purified. The canal has quite a
descent to Lockport, and the water-power is to be availed of in
generating electricity. The city water-supply is drawn from cribs out
in the lake through four systems of tunnels, aggregating twenty-two
miles, furnishing an ample service, and pumping-stations in various
locations elevate the water in towers to secure sufficient head for
the flow into the buildings. The chief of these towers, a solid stone
structure alongside the lake, rises one hundred and sixty feet, the
huge pumping-engines forcing a vast stream constantly over its top.
[Illustration: _Lincoln Monument, Lincoln Park, Chicago_]