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Geo. W. Richardson: 812

Geo. W. Richardson 812 Direct Reading Enhanced Mannheim

Details of: Geo. W. Richardson - 812

Type? A generic name (e.g. Rietz) or function/use for specialist models (e.g. Meteorology) for grouping similar models across makers. If not “standard” 25cm linear length, preceded by the form (i.e. Demonstration, Desktop, Pocket, Waistcoat, Keyring, Lilliput or Book) + if needed, qualification to distinguish between versions (e.g. early or late). Direct Reading Enhanced Mannheim
Sort? L/C/D/T/W/X where L=Linear, C=circular, D=Drum, T=tubular, W=watch, X=miscellaneous (i.e. the rest) L
Construction? Basic construction form of the body i.e. Closed/solid frame or Open frame or Duplex or Other Closed/solid frame
Material? Basic description: ivory/bone/wood/bakelite/plastic/metal/cardboard or combinations e.g. wood/veneered, wood/painted, etc sheet copper/celluloid
Length? 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. 10"
Scales front? 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 S,A / B,C / D,T,L
Scales back? 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
Cursor type? Basic description (incl. material) + no. of hairlines, etc on any cursor(s) or alternative to a cursor - e.g. a stylus sheet copper/plastic - 1 hairline
Condition? Cn where n = 0-6  condition/quality scale where 0 = brand new in box & 6 = broken   C5
Date? YYYY for year(s) of production or an approximation/range of years 1911-1913
Extras? Basic description of any accessories - e.g. case or stand + where relevant, an accreditation for image, etc brown lined covered stiff carboard box (part) - image courtesy of ISRM
Instructions? Details like “on back of rule” and/or language of instruction sheet/booklet - generic or instructions for common layouts usually not listed English book of instructions - digital copy courtesy of ISRM
Booklet (PDF)? Downloadable .PDF copy of unusual or uncommon model specific instructions download
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

Keyholes (top left & bottom right) are direct reading line-up points for a table of codes on the back. By aligning a chosen code in the keyhole the slide is automatically set for the chosen calculation. Provisional patent no. 3-26-12 on cursor - full patents = 1911 US982876 & in 1912 US1021484 . ​

In-Out? MM-YYYY / MM-YYYY of the date added/left the collection or <YYYY if exact MM-YYYY no longer known <2005/

All of:  Geo. W. Richardson new search?

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