How was the American army recruited during the War of 1812? The question is more complicated than it may seem. There was no national draft, and the standing regular US Army was minuscule. The President and Congress were faced with a huge challenge in the summer of 1812. Mobilization, training, equipping and supply of forces to defend the borders of the United States (as well as to invade Canada) had to be accomplished by Federal officials and officers without any experience of running a full-scale war.
When Congress authorized an expansion of the Army on the brink of war, a publishing house called Websters and Skinners, of Albany, New York, issued this pamphlet for the reference of newly-appointed officers. This volume reprinted the articles of war determined by an Act of Congress, as well as the general orders of the Secretary of War. Of particular interest are the guidelines for recruiting officers. Note on page 116, that if there are no Army musicians available to accompany the recruiting party, the officer is authorized to hire civilian musicians for 15 dollars a month (rations included).
Messrs Webster and Skinner must have been canny businessmen: they offered a brief selection of military manuals and how-to books at the end of the volume...
At least one of these books, Hoyt's "Practical Instructions", is also available on Google Books for the curious browser or novice officer.