A generic name (e.g. Enhanced Mannheim) or function/use for special models (e.g. Meteorology) as an aid to grouping similar models across makers. If not the “standard” 25cm linear length, proceeded by the form (e.g. Demonstration, Desktop, Pocket, Waistcoat, Lilliput or Book) + suffix when needed to distinguish between different versions (e.g. early or late).
||Child's Multiplication Table Teaching Aid/Pencil Case|
L/C/D/T/W/X where L=Linear, C=circular, D=Drum, T=tubular, W=watch, X=miscellaneous (i.e. the rest)
Basic construction form of the body i.e. Closed/solid frame or Open frame or Duplex or Other
Basic description: ivory/bone/wood/bakelite/plastic/metal/cardboard or combinations e.g. wood/veneered, wood/painted, etc
Mostly linear length in cm or " (inches) of the D scale but excluding any extensions. For circular/watch slide rules it is the diameter but for helical/tubular/drum slide rules it is the overall scale length. For other calculating aids it is the physical length.
Standard (not maker’s) symbols for scales on front face e.g. A = X² (1-100) but § = generic symbol (signum sectiōnis) for any non-standard scale + scales between solidi / / are on the slide(s) whereas scales after vertical line | or after reversed solidus \ are on a straight or bevelled top or bottom side edge
Standard (not maker’s) symbols for scales on back face e.g. S = sine (5° to 90° & 85° to 0°) or sin(x) but § = generic symbol (signum sectiōnis) for any non-standard scale + scales between solidi / / are on the back of slide(s) but scales listed after / / - notation are on another surface e.g. back of stock or inside a lid
Basic description (incl. material) + no. of hairlines, etc on any cursor(s) or alternative to a cursor - e.g. a stylus
||none - not needed|
Cn where n = 0-6 condition/quality scale where 0 = brand new in box & 6 = broken
YYYY for year(s) of production or an approximation/range of years
Basic description of any accessories - e.g. case or stand + where relevant, an accreditation for image, etc
Details like “on back of rule” and/or language of instruction sheet/booklet - generic or instructions for common layouts usually not listed
| Comments ||?
Any special or noteworthy traits + significant use-related facts + pertinent details of scales/tables in well of stock + any significant tables, etc on the back of the stock
Invented & patented (GB167699) as a teaching aid for 1 - 20 multiplication tables by Percy Darnley & Barnett Richards in 1920 - possibly inspired by earlier 1885 German patent (DE33155) of Peter Wiesenmüller - dark-blue & green versions also made + German 4-colour series branded ROKA
MM-YYYY / MM-YYYY of the date added/left the collection or <YYYY if exact MM-YYYY no longer known