Lyon welcomed the appointment of Fremont to command, because he felt the need of having a superior officer at hand who would appreciate the urgency of the situation, and stand between him and the authorities at Washington, who apparently did not understand the emergency, were not honoring his requisitions for money, arms, and supplies, and who were drawing to the eastward the troops that Lyon felt ought to be sent to him. It was also satisfactory to him that the State of Illinois was in the Department, since the important point of Cairo should be administered with reference to controlling the situation in southeastern Missouri.
The first distrust of Fremont came from his deliberation in repairing to his command. The people of Missouri felt very keenly that no time should be lost in the General arriving on the spot and getting the situation in hand, but in spite of all importunities, Fremont lingered for weeks in New York, and it required a rather sharp admonition from the War Department to start him for St. Louis, where he arrived as late as July 25.
Lyon's prompt advance upon Jefferson City now bore fruit in another direction. The Union people of Missouri decided that as Gov. Jackson, Lieut-Gov. Reynolds and other State officials had abandoned the State Capital to engage in active rebellion against the United States, the State Convention, which had been called to carry the State out of the Union, but which had so signally disappointed the expectations of its originators, should reconvene, declare the State offices vacant, and instate a loyal Government A strong party desired that a Military Governor should be appointed, and urged Col. Frank P. Blair for that place, but he refused to countenance the project. The Convention, by a vote of 56 to 25, declared the offices of Governor, Lieutenant-Governor and Secretary of State vacant, and elected Hamilton R. Gamble Governor, Willard P. Hall Lieutenants Governor, Mordecai Oliver Secretary of State, and George A. Bingham Treasurer. An oath of loyalty was adopted to be required of all citizens before being allowed to vote, and to be taken by all incumbents of office and all who should be qualified for office thereafter.
Gov. Jackson established his Capital at Lamar, in Barton County, about 30 miles south of the Osage, and the men who had been appointed to command the Militia Districts began to come in with their contingents. None seemed to know about the flanking columns which had been sent out toward Springfield, to take the line of the Osage in the rear, and they were astounded when forces under Sweeny and Sigel, which had dispersed the gathering Militia before them at Holla, Lebanon, and other intervening points, reached Springfield, and began sending out from there expeditions to Neosho, Ozark, Sarcoxie and other towns in the southwestern corner. Col. Franz Sigel, who had shown much activity and enterprise, learned at Sarcoxie that several divisions of State Guards under Gens. Rains, Parsons, Slack and Clark were to the north of him, and the Governor and Gen. Price were endeavoring to bring them together in order to turn upon and crush Gen. Lyon in his advance from Boonville. Sigel's men, who were anxious to accomplish something decisive before the expiration of their three months' term, brought about a decision in their commander's mind to march upon the force encamped upon Pool's Prairie, whip and scatter it, and then attack the other forces in turn.
After making the necessary detachments to guard his flanks and rear, Col. Sigel had under his command nine companies of the 8d Mo., 550 men under Lieut.-Col. Hassendeubel; seven companies of the 5th Mo., under Col. Charles E. Salomon, 400 men, and two batteries of light artillery, four guns each, under Maj. Backof.
After a hard day's march of 22 miles in very hot weather, Col. Sigel came, on the evening of July 4, about one mile southeast of Carthage, on the south side of Spring River. He made preparations to attack the enemy, reported to be from 10 to 15 miles in his front.
That night Gov. Jackson received news of Sigel's advance, and gathered his forces to resist him. He had already concentrated many more men than Sigel had expected, and had with him seven pieces of artillery. Most of his men carried the arms which they had brought from home, and were arranged, according to the provisions in the Military Bill, into divisions, of which there were no less than four present. The Second Division, commanded by Brig.-Gen. James S. Rains, who afterward attained much reputation in the Confederate army, had present 1,208 infantry and artillery and 608 cavalry. The Third Division, commanded by Gen. John B. Clark, also to attain eminence in the Confederate army, had 365 present. The Fourth Division, commanded by Gen. Wm. Y. Slack, later a Brigadier-General in the Confederate army, had 500 cavalry and 700 infantry. The Sixth Division, commanded by Gen. Monroe M. Parsons, who served with distinction throughout the war, had altogether about 1,000 men and four pieces of artillery. The official returns show that Gov. Jackson had thus 4,375 men with seven guns to oppose something over 1,000 men with eight guns under Col. Sigel. The Union force was strong in artillery, while the Confederates were powerful in cavalry, of which the Unionists had none. Both sides were poorly supplied with ammunition, especially for the cannon, and loaded these with railroad spikes, bits of trace chains, etc.