To show the importance of these lake-harbors, and the vast amount of commerce which depends upon them, and which has grown up within the last twenty years, we will give an extract from another of Col.  Graham’s very interesting Reports, upon the Chicago harbor.

“The present vast extent and rapidly increasing growth of the commerce of Chicago render it a matter of absolute necessity, in which not only Illinois, but also a number of her neighboring States are deeply interested, that her harbor should be kept in the best and most secure state of improvement, so as always to afford, during the season of navigation, a safe and easy entrance and departure for vessels drawing at least twelve feet water.

“The States which are thus directly interested in the port of Chicago are New York, Pennsylvania, Ohio, Michigan, Indiana, Illinois, Wisconsin, and Minnesota.  The shores of all these are washed either by Lake Michigan or the other Great Lakes, with which Chicago has a direct and very extensive commerce through the St. Clair flats.  The other States and Territories, which do not reach to the Great Lakes, but which are nevertheless greatly interested in the preservation of Chicago harbor, are Iowa and Missouri, and Nebraska and Kansas.  A very large portion of the wheat and other grain produced in those last-mentioned States and Territories will be brought by railroads to the port of Chicago, to be shipped thence to the Eastern Atlantic markets.

“The average amount of duties received annually at the Chicago custom-house for three years, 1853, ’54, and ’55, was $377,797.86.  The imports at Chicago for 1855 were,—­

By lake shipment,                $100,752,304.41
" Illinois and Michigan Canal,      7,426,262.35
" Railroads,                       68,481,497.90

  Total imports in 1855, $196,660,064.66

Exports.

By lake shipment, $34,817,716.32 " Canal, 79,614,042.70 " Railroads, 98,521,262.86 ---------------- Total value of exports in 1855, $212,953,021.88

“Aggregate value of imports and exports at Chicago in the year 1855, $409,613,086.54.[B]

[Footnote B:  This is more than half of the value of all the exports and imports of the Union in the year 1860, King Cotton included.]

“These statistics have been obtained by much labor and perseverance, with a view to the strictest accuracy.  The result has amply justified the labor; for the published statistics of this commerce, which have gone forth to the country through the newspaper-press of the city, fall far short of its actual extent.  On discovering this fact, I felt it to be a matter of duty to obtain the information directly from the only authentic sources, namely, the custom-house, mercantile, and warehouse records.

“Such are the claims which, in a civil point of view, are presented in behalf of the preservation of this harbor.