The Slide Rule Trading Co., Paul Ross

Hemmi Slide Rule Catalogue Raisonne

Front Scales

Scales are listed in order from top to bottom.
Scale names are the labels actually on the slide rule or in Hemmi documentation.  If the scale name was not easily determinable, then the scale name is the name in modern use.
The “front” of duplex slide rules is arbitrarily defined to be the side with the longer stator down.  This is usually, but not always, the side carrying the brand name and model number and the head of the body screws.

Scale subdivisions changed from time to time.  In particular, on some rules all, some, or none
of the principal subdivision between 1 and 2 on the C and D scales were explicitly numbered at different
times.  It is beyond our ability to note such variations.