Letter from Roswell Shurtleff in Hanover, New Hampshire to Nathaniel Shattuck with an explanation of the origin of the process of extraction of cube and square roots. Writer thought he first solved the process in 1801, with Caleb Butler, but later discovered that Shattuck had originated the idea of using blocks which was explained later in Adams' arithmatice. (typewritten). Includes Mss 906103.