By himself, however, he would have been helpless. He required assistance. He was obliged to have chiefs of the several arms about him,—a chief of engineers, of artillery, of cavalry, and chiefs of the several divisions of infantry.
General Barry was his chief of artillery. To him was assigned the duty of organizing this arm of the service. We learn from his Report, that, "when Major-General McClellan was appointed to the command of the 'Division of the Potomac,' July 25th, 1861, a few days after the first Battle of Bull Run, the whole field-artillery of his command consisted of no more than parts of nine batteries, or thirty pieces of various, and, in some instances, unusual and unserviceable calibres. Most of these batteries were also of mixed calibres. My calculations were based upon the expected immediate expansion of the 'Division of the Potomac' into the 'Army of the Potomac,' to consist of at least one hundred thousand infantry. Considerations involving the peculiar character and extent of the force to be employed, the probable field and character of operations, the utmost efficiency of the arm, and the limits imposed by the as yet undeveloped resources of the nation, led to the following general propositions, offered by me to Major-General McClellan, and which received his full approval."
These propositions in brief were,—
1st. "That the proportion of artillery should be in the ratio of at least two and a half pieces to one thousand men."
2d. "That the proportion of rifled guns should be one-third, and of smooth bores two-thirds."
3d. "That each field-battery should, if practicable, be composed of six guns."
4th. "That the field-batteries were to be assigned to 'divisions,' and not to brigades."
5th. "That the artillery reserve of the whole army should consist of one hundred guns."
6th. "That the amount of ammunition to accompany the field-batteries was not to be less than four hundred rounds per gun."
7th. That there should be "a siege-train of fifty pieces."