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Heath & Co.: Hezzanith

Heath & Co Hezzanith Navigational

Details of: Heath & Co. - Hezzanith

Type? A generic name (e.g. Enhanced Mannheim) or function/use for special models (e.g. Meteorology) as an aid to grouping similar models across makers. If not the “standard” 25cm linear length, proceeded by the form (e.g. Demonstration, Desktop, Pocket, Waistcoat, Lilliput or Book) + suffix when needed to distinguish between different versions (e.g. early or late). Navigational 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 wood/celluloid veneers
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. 10¾"
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 inch \ A / B,C / D | cm
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 / S,L,T /
Cursor type? Basic description (incl. material) + no. of hairlines, etc on any cursor(s) or alternative to a cursor - e.g. a stylus plastic - 1 hairline
Condition? Cn where n = 0-6  condition/quality scale where 0 = brand new in box & 6 = broken   C2
Date? YYYY for year(s) of production or an approximation/range of years 1930s or 1940s
Extras? Basic description of any accessories - e.g. case or stand + where relevant, an accreditation for image, etc mottled dark-green linen covered box (Thornton box marks)
Instructions? Details like “on back of rule” and/or language of instruction sheet/booklet - generic or instructions for common layouts usually not listed UKSRC reprint - maunal especifially compiled as a Seaman's aid to coastal navigation
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

Probably Thornton-made (similar to PIC 3654) - reduction scale (not Haversines) by Captain Charles Le Patourel in well of stock for correcting degrees above horizon when a star transcends its meridian - Le Patourel compiled tables of nautical data also on back

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:  Heath & Co. new search?

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