Originally Posted by Tuebor
One can make the same argument for the post-legion army as being a "combined arms division."
No, it cannot. The two organizations were entirely different, especially when the new commander was Wilkerson after Wayne's untimely death.
Regarding Peter's horse artillery company and the disposition of the horses, which were sold by the order you referenced (discretionary or not, it is still an order, and the expense of the horses was the issue), the following is offered from two credible secondary sources:
Cannonade by Fairfax Downey, 64-65:
'That first American horse artillery...commanded by Captain George Peter, held high promise. Peter staged a drill for Congress on July 4, 1808, greatly impressing that body. Galloping three miles, he dismounted, unlimbered, and fired a national salute; then returned to the starting point and fired a second salute-in all twenty-two minutes. He made a route march from Baltimore to Washington at better than six miles an hour-good time even by World War I standards and a remarkable rate over the plodding guns of the Revolution. Cheered by spectators, the battery paraded smartly down Pennsylvania Avenue...Next the battery struck out for New Orleans, crossing the Alleghenies handily in midwinter, and finishing the journey by Mississippi flatboats. Then it was ignominiously stalled in the Louisiana mud when the new secretary of war, William Eustis, former contract surgeon and a small-minded politician, ordered its horses sold on the ground that forage was too expensive. Peter, his fine battery immobilized and ruined, resigned his commission in disgust.'
The references used were Historical Sketch of the Organization, Administration, Material and Tactics of the Artillery, United States Army by William Birkhimer; The Beginning of the US Army 1783-1812 by James Jacobs; Military Collector and Historian Journal, September 1952, article by Harry Larter; Niles' Register, LXXII.
History of the United States Army by Russell Weigley, 111:
'The act of April 12, 1808, included a regiment of light artillery in its increases of the Army. Captain George Peter's company of the new regiment was issued sufficient horses to mount itself and thus to become the first American battery of light artillery in the New Napoleonic style. On July 4, 1808, Peter's company staged an impressive demonstration for Congress, and it soon conducted a route march from Baltimore to Washington at the then remarkable speed of six miles an hour. Unfortunately, the experiment proved abortive. After Jefferson left office, President Madison's Secretary of War decided the horses were a waste of money and sold them. No other company of the Regiment of Light Artillery was mounted before the War of 1812; during the war a few were, but only briefly.'
Weigley references Downey.