Usually a generic name preceded by the form if not standard linear length - e.g. Pocket Enhanced Mannheim. For special models often supplemented by its function/use - e.g. meteorology. Sometimes a suffix is 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 length in cm or ” (inches) of the D scale but excluding any scale extensions. But for circular or watch slide rules it is the diameter & for tubular or drum slide rules it is the overall linear scale length. For other mechanical aids it is the physical length.
Mostly standardised (not maker’s) symbols for scales on front of stock e.g. A = X² (1-100) but § = generic symbol for any non-standard scale. Scales between solidi (/ /) are on the slide(s) whereas a vertical line ( | ) or reversed solidus ( \ ) + a symbol denotes scale(s) on a straight or bevelled edge.
Mostly standardised (not maker’s) symbols for scales on back of stock e.g. S = sine (5° to 90° & 85° to 0°) or sin(x) but § = generic symbol for any non-standard scale. Scales between solidi (/ /) are on the back of the slide(s).
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 based on Herman van Herwijnen’s condition/quality scale
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