J. M. Scribner developed the Scribner log rule in 1846.
The Scribner Rule is called a diagram rule because the original numbers were derived by fitting boards into perfect circles representing the ends of logs.
The Scribner rule was adapted by the Lufkin Rule Company and published as decimal A, B and C rules.
A change was made to the basic Scribner rule to make it easier to apply. This new rule the "Scribner Decimal C Rule" is different from the standard Scribner rule in that all volumes are rounded to the nearest 10 board feet.