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Dennert & Pape: QR 41

Dennert & Pape QR 41 Desktop

Details of: Dennert & Pape - QR 41

Type? 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. 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 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. 50cm
Scales front? 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. cm \ § / §,§ / § | 1:25
Scales back? 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).
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 based on Herman van Herwijnen’s condition/quality scale 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

QR = “Quadrat-Rechenschieber” - commissioned by “Gebr. Wichmann” (stamp in well) - probably classroom training aid for anti-aircraft gunners - 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/

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