Although Karl King was not schooled in composition, he did study the principles of music theory on his own. This 1883 Schneider's Treatise On Thorough Bass and Harmony from McKenzie and Brown Manufacturing Company of Torrington, Connecticutt, was found in the King family archives. It is believed to be the book which Karl King studied to learn the rules of theory and harmony.
The volume is autographed by A. I. McKenzie.
Note that this book was translated and adapted to the Wants of Young Students.
Pasted in the front of the book is a sheet explaining the name of each tone of the scale.