IMPROVEMENTS IN NORTH AMERICAN HYDROGRAPHY. 627 
into the Illinois. The mean discharge by this channel does not 
much exceed 23,000 cubic feet per minute, but it would be 
quite practicable to enlarge its cross-section indefinitely, and 
the flow through it might be so regulated as to keep the Llinois 
and the Mississippi at flood at all seasons of the year. The 
increase in the volume of these rivers would augment their 
velocity and their transporting power, and, consequently, the 
erosion of their banks and the deposit of slime in the Gulf of 
Mexico, whilethe opening of a communication between the lake 
and the affluents of the Mississippi, unobstructed except by 
locks, and the introduction of a large body of colder water 
into the latter, would very probably produce a considerable 
effect on the animal life that peoples them. The diversion of 
water from the common basin of the great lakes through a new 
channel, in a direction opposite to their present discharge, 
would not be absolutely without influence on the St. Lawrence, 
though probably this effect might be too small to be readily 
perceptible.* 
In an able and interesting article in a California magazine, 
Dr. Widney has suggested a probable cause and a possible 
remedy for the desiccation of south-eastern California referred 
to in a former chapter. The Colorado Desert which lies con- 
siderably below the level of the waters of the Gulf of Califor- 
nia, and has an area of about 4,000 square miles, evidently 
* From Reports of the Canal Commissioners of the State of Illinois, and 
especially from a very interesting private letter from William Gooding, Esq., 
an eminent engineer, which I regret I have not space to print in full, I learn 
that the length of the present canal, from the lake to the River Illinois, is 
101 miles, with a total descent of a trifle more than 145 feet, and that it is 
proposed to enlarge this channel to the width of one hundred and sixty feet, 
with a minimum depth of seven, and to create a slack-water navigation in the 
Illinois by the construction of five dams, one of which is already completed. 
The descent for the outlet of the canal at La Salle on the Illinois to the 
Mississippi is twenty-eight feet, the distance being 230 miles. The canal thus 
enlarged would cost about $16,000,000, and it would establish a navigation for 
vessels of 1,206 to 1,500 tons burden between Lake Michigan and the Mis- 
sissippi, and consequently, by means of the great lakes and the Welland canal, 
between the St. Lawrence and the Gulf of Mexico. 
