Notes: "The Dietzgen Phillips slide rule falls into the broad category of “improved Mannheim” slide rules. Not quite a Rietz – it would need a CI scale for that - but better than a Mannheim. The scales on the front are A | B, R, C | D, there is a K scale (labeled E) on the lower edge, and S, L, and T scales on the back of the slide. The Phillips’ contribution is the “R” scale, which is an inverse B scale that really should be called a BI scale. The value of this scale is that it gives the Phillips the ability to perform multiplications with three terms (A x B x C) with only one setting of the slide. "