A generic name (e.g. Rietz) or function/use for specialist models (e.g. Meteorology) for grouping similar models across makers. If not the “standard” 25cm linear length, preceded by the form (i.e. Demonstration, Desktop, Pocket, Waistcoat, Lilliput or Book) & when needed, a suffix to distinguish between versions (e.g. early or late).
||Electro poly-slide (2)|
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 the linear length of the D scale (in cm or inches) 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
||translucent yellow & black duplex - 1 hairline + peripheral hairline & gauge marks|
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
||black linen covered cardboard case with box marks for J. David & Son + two flyers|
Details like “on back of rule” and/or language of instruction sheet/booklet - generic or instructions for common layouts usually not listed
Downloadable .PDF copy of unusual or uncommon model specific instructions
| 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
Copyrighted & patented (US1560599) by Charles C. Moler in 1925 - special commission for The Potomac Edison Company, Maryland, USA (Moler’s employer) - 4 adjustment screws in top side edge - besides preventing voltage flicker on electrical distribution lines it could save money by avoiding expense of higher grade of cable when not needed - read more ....
MM-YYYY / MM-YYYY of the date added/left the collection or <YYYY if exact MM-YYYY no longer known