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 water-shed, 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 to-wards 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.