Long before the present metropolis had arrived at the title and dignity of a city, the advantage to be derived from a waterway between Lake Michigan and the Illinois River, and thence to the Mississippi, was well understood. The scheme was, in fact, considered of sufficient importance to call for legislation as early as 1822, in which year an act was passed authorizing the construction of a canal having this object. It was not commenced, however, till 1836, and was opened to navigation in the spring of 1848. This canal extended from Chicago to La Salle, a distance of 97¼ miles, and it had a fall of 146 ft. to low water in the Illinois River (see Fig. 1). It was only a small affair, 6 ft. deep, and 60 ft. wide on the surface; the locks were 110 ft. long and 18 ft. wide. The summit level, which was only 8 ft. above the lake, was 21 miles in length. This limited waterway remained in use for a number of years, until, in fact, the growth of Chicago rendered it impossible to allow the sewage to flow any longer into the lake. In 1865 the State of Illinois sanctioned widening and lowering the canal so that it should flow by gravity from Lake Michigan. The enlargement was completed in 1871, by the city of Chicago, and the sewage was then discharged toward the Illinois River. But the flow was insufficient, and in 1881 the State called on the city to supplement the flow by pumping water into the canal. [Illustration: FIG. 1] In 1884, engines delivering 60,000 gallons a minute were set to work and remedied the evil for a time, so far as the city of Chicago was concerned, but the large discharge of sewage through the sluggish current of the canal and into the Illinois River proved a serious and ever-increasing nuisance to the inhabitants in the adjoining districts. To enlarge the existing canal, increase the volume and speed of its discharge, and to alter the levels, so that there shall be a relatively rapid stream flowing at all times from Lake Michigan, appears the only practical means of affording relief to the city, and immunity to other towns and villages lying along the route of the stream.