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.

The physical nature of the country is well suited for carrying out
such a project on a scale far larger than that required for sewage
purposes, and works thus carried out would, to a small extent, restore
the old water _regime_ in this part of the continent. Before the vast
surface changes produced during the last glacial period, three of the
great lakes--Michigan, Huron and Superior--discharged their waters
southward into the Gulf of Mexico by a broad river. The accumulation
of glacial debris changed all this; the southern outlet was cut off,
and a new one to the north was opened near where Detroit stands,
making a channel to Lake Erie, which then became the outlet for the
whole chain by way of Niagara. A very slight change in levels would
serve to restore the present _regime_. Around Lake Michigan the land
has been slightly raised, the summit above mean water level being only
about 8 ft. Thirty miles from the south shore the lake level is again