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Gebr. Wichmann: QR 41

Gebr. Wichmann QR 41 Desktop

Details of: Gebr. Wichmann - QR 41

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). Desktop Military Artillery Squaring
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 plastic
Length? Mostly the linear length of the D scale (in cm or inches) excluding any extensions. For circular/watch slide rules the diameter but for helical/tubular/drum slide rules it is the overall scale length. For other calculating aids it is the physical length or LxWxH. 50cm
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 cm \ § / §,§ / § | 1:25
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 metal/glass - 1 hairline
Condition? Cn where n = 0-6  condition/quality scale where 0 = brand new in box & 6 = broken   C3
Date? YYYY for year(s) of production or an approximation/range of years 1941
Extras? Basic description of any accessories - e.g. case or stand + where relevant, an accreditation for image, etc black stiff carboard case with Faber-looking box marks but from D&P
Instructions? Details like “on back of rule” and/or language of instruction sheet/booklet - generic or instructions for common layouts usually not listed German
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

OEM by Dennert & Pape + QR = Quadrat-Rechenschieber & 41 = year of production - commissioned by “Gebr. Wichmann” (stamp in well) - probably classroom training aid for anti-aircraft gunners as it was specially designed for solving Pythagorean triangles + layout consists of two pairs (upper set 0 - 50 & lower set 0 - 15.8) of non-logarithmic independent root scales (no interaction) derived from a set of tables by German Peter Timpenfeld & first published in 1888​ - non-conventional use of a cursor purely for positional summing of the squared values

In-Out? MM-YYYY / MM-YYYY of the date added/left the collection or <YYYY if exact MM-YYYY no longer known <2010/

All of:  Gebr. Wichmann new search?

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QR 41 Desktop Military Artillery Squaring