After the rebuilding, the water question came up for discussion again. In spite of all that had been done to protect the water supply, the increasing sewage of the city, carried by the river into the lake, at times still made the water unfit to drink. The one way of getting pure water was to prevent the river from flowing into the lake. This could be done only by building a new canal, large and deep enough to change the flow of the river away from the lake. Such a canal was finally completed in 1900, after eight years' work and at a cost of over $75,000,000. It is 28 miles long, 22 feet deep, and 165 feet wide, and it connects the Chicago River with the Des Plaines, a branch of the Illinois River. A large volume of water from Lake Michigan continually flushes this immense drain, carrying the sewage away. The Chicago River no longer flows into the lake, and at last the danger of contaminated drinking-water from this source is past. [Illustration: BUSY SCENE AT ENTRANCE TO CHICAGO RIVER] One dream of the builders of the canal has not yet been realized. They called it the Chicago Drainage and Ship Canal, in the hope that it might some day be used for shipping purposes as well as for draining the river. This cannot happen, however, till the rivers which it connects are deepened and otherwise improved. Such has been the history of the growth of Chicago--to-day the greatest railroad center and lake port in the world. It is now the second city in size in America and ranks fourth among the cities of the world. The port of Chicago owes much to the Chicago River, which has been repeatedly widened, deepened, and straightened. It is to-day one of the world's most important rivers, commercially considered. After extending about one mile westward from the lake, the river divides into two branches, one extending northwest, the other southwest. Many docks have been built along its fifteen miles of navigable channel, and its banks are lined with factories, warehouses, coal yards, and grain elevators. [Illustration: Courtesy of Central Trust Company of Illinois, Chicago CHICAGO'S FIRST GRAIN ELEVATOR] These grain elevators are really huge tanks where the grain is stored and kept dry until time to reship it. There are many of them along the river, and they bear witness to the fact that Chicago is the world's greatest grain center. In 1838 the city received only seventy-eight bushels of wheat. This was brought in by wagons rumbling across the unbroken prairie. Canal boats and railroads have taken the place of the wagons of early days and every year bring hundreds of millions of bushels of grain from the West to the elevators along the Chicago River. Though much of the grain remains here but a short time and is then shipped to other points, a great quantity is made into flour in the city's many flourishing mills. [Illustration: A GRAIN ELEVATOR OF TO-DAY]