A State convention, elected to pass a secession ordinance, resulted, unexpectedly to the conspirators, in the return of a majority of Union delegates, who voted down the secession program and adjourned to the following December.  Thereupon, the secession governor ordered his State militia into temporary camps of instruction, with the idea of taking Missouri out of the Union by a concerted military movement.  One of these encampments, established at St. Louis and named Camp Jackson in honor of the governor, furnished such unquestionable evidences of intended treason that Captain Lyon, whom President Lincoln had meanwhile authorized to enlist ten thousand Union volunteers, and, if necessary, to proclaim martial law, made a sudden march upon Camp Jackson with his regulars and six of his newly enlisted regiments, stationed his force in commanding positions around the camp, and demanded its surrender.  The demand was complied with after but slight hesitation, and the captured militia regiments were, on the following day, disbanded under parole.  Unfortunately, as the prisoners were being marched away a secession mob insulted and attacked some of Lyon’s regiments and provoked a return fire, in which about twenty persons, mainly lookers-on, were killed or wounded; and for a day or two the city was thrown into the panic and lawlessness of a reign of terror.

Upon this, the legislature, in session at Jefferson City, the capital of the State, with a three-fourths secession majority, rushed through the forms of legislation a military bill placing the military and financial resources of Missouri under the governor’s control.  For a month longer various incidents delayed the culmination of the approaching struggle, each side continuing its preparations, and constantly accentuating the rising antagonism.  The crisis came when, on June 11, Governor Jackson and Captain Lyon, now made brigadier-general by the President, met in an interview at St. Louis.  In this interview the governor demanded that he be permitted to exercise sole military command to maintain the neutrality of Missouri, while Lyon insisted that the Federal military authority must be left in unrestricted control.  It being impossible to reach any agreement, Governor Jackson hurried back to his capital, burning railroad bridges behind him as he went, and on the following day, June 12, issued his proclamation calling out fifty thousand State militia, and denouncing the Lincoln administration as “an unconstitutional military despotism.”

Lyon was also prepared for this contingency.  On the afternoon of June 13, he embarked with a regular battery and several battalions of his Union volunteers on steamboats, moved rapidly up the Missouri River to Jefferson City, drove the governor and the secession legislature into precipitate flight, took possession of the capital, and, continuing his expedition, scattered, after a slight skirmish, a small rebel military force which had hastily collected at Boonville.  Rapidly