We have received a copy of the Chicago Tribune containing a full "exposure," as it is called, of the great conspiracy in the Western and Middle States to break up what remains of the late United States. It appears that as early as June last some prominent citizens of St. Louis were arrested by Sanderson, the provost-marshal of the city, upon the charge of being conspirators, but the cause of the arrests was smothered up. Recently, however, more arrests were made, and this time too many to be kept quiet. The St. Louis correspondent of the Tribune furnishes that paper with very lengthy accounts of the "great conspiracy," from which we extract the following:
‘ Of the citizens arrested, a number were refused parole and bond, and continued imprisoned. It now leaks out that those men have been found to be influential officers of an extensive association, co-operating with a similar one in rebeldom, looking to the establishment of a Northwestern Confederacy, (!) and including as a part of the programme the forcible ejection of Mr. Lincoln from the executive office! The details of this matter might relieve the statement of any improbability arising from the apparent hopelessness of such an enterprise; but, doubtless, for good reasons, they are not at present permitted to be published. Colonel Sanderson has, we understand, unravelled the plot, not without the expenditure of much time and patience, as well as labor — it being necessary, with extreme caution, to gain the introduction of trustworthy Unionists into the councils of the suspected parties. The testimony collected, embodying the reports of his agents and proceedings of the secret "Lodges" or "Temples," cover, it is said, a full ream of foolscap paper, and has been transmitted in a report to General Rosecrans to the authorities at Washington.
’ The projects of these conspirators in this department have, of course, been "headed off, " and it is be hoped that they will be disposed of in like summary manner elsewhere.
The evidence is said to implicate many public men, and proves the organization formidable and dangerous, if undiscovered. One of the arrested parties vainly offered a bond of $500,000 for his release.
The gathered facts warrant the belief that the following may be relied upon as a tolerable correct exposition of a conspiracy whose numbers, treasonable purposes, and effective organization, are certainly calculated to startle the loyal people of this country and to excite grave apprehensions of a fresh peril:
