Notes: "The Hemmi Model 2664 is an ‘enhanced Mannheim’ type slide rule, with many additional scales, but it deviates from the Mannheim pattern by deleting the B scale, moving the A scale to the bottom of the lower stator, and including CF and DF scales. The C & D scales had long since replaced the A & B scales as the primary scales used for multiplication and division, and the CF and DF scales retained the “can’t run off the end” property of the A & B scales but with the advantage of full-length precision"
