ALRO Patent System 200R circular slide rule with concentric scales and central patent plate in its metal housing.

ALRO Patent System 200R Circular Slide Rule with Wooden Case and Manual

€225,00 EUR
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ALRO Patent System 200R circular slide rule with concentric scales and central patent plate in its metal housing.
  • ALRO Patent System 200R circular slide rule with concentric scales and central patent plate in its metal housing.
  • Close-up of the ALRO 200R circular slide rule showing the ALRO Patent plate, The Hague Holland marking and graduated scales.
  • ALRO 200R circular slide rule with its metal cover open, showing the main dial and part of the reference scale inside the lid.
  • Circular reference scale inside the hinged metal lid of the ALRO 200R slide rule, showing age-related discoloration.
  • Dutch ALRO Rekenschijven instruction manual for types 100 R and 200 R, with creases, discoloration and worn edges.
  • Open Dutch ALRO circular slide rule manual showing the introductory page headed Ronde ALRO Rekenschijven.
  • Closed metal housing of the ALRO 200R circular slide rule, showing its rounded lid, hinge and surface wear.
  • Closed wooden storage case for the ALRO 200R circular slide rule, with visible wood grain and a metal front clasp.
  • ALRO Patent System 200R circular slide rule with concentric scales and central patent plate in its metal housing.
  • Close-up of the ALRO 200R circular slide rule showing the ALRO Patent plate, The Hague Holland marking and graduated scales.
  • ALRO 200R circular slide rule with its metal cover open, showing the main dial and part of the reference scale inside the lid.
  • Circular reference scale inside the hinged metal lid of the ALRO 200R slide rule, showing age-related discoloration.
  • Dutch ALRO Rekenschijven instruction manual for types 100 R and 200 R, with creases, discoloration and worn edges.
  • Open Dutch ALRO circular slide rule manual showing the introductory page headed Ronde ALRO Rekenschijven.
  • Closed metal housing of the ALRO 200R circular slide rule, showing its rounded lid, hinge and surface wear.
  • Closed wooden storage case for the ALRO 200R circular slide rule, with visible wood grain and a metal front clasp.
ALRO Patent System 200R Circular Slide Rule with Wooden Case and Manual

ALRO Patent System 200R Circular Slide Rule with Wooden Case and Manual

€225,00 EUR
A tangible piece of Dutch calculating history: this ALRO Patent System Type 200R circular slide rule comes with a wooden storage case and the Dutch-language instruction manual “Gebruiksaanwijzing Alro Rekenschijven” for types 100 R & 200 R. According to the information supplied to us, this is a high-quality prewar technical instrument from the 1930s, manufactured in The Hague, the Netherlands. The wooden storage case and Dutch instruction manual are described as original. This provenance and dating have not been independently verified. The combination of the circular slide rule, metal housing, wooden case and accompanying documentation makes this an appealing collectible for enthusiasts of historical calculating instruments, technical curiosities and the history of science. The scale is marked “SYST. ALRO 200R”; the central plate bears the markings “ALRO PATENT” and “The Hague Holland”. Brand and system: ALRO Patent System Type: 200R Dimensions: 15 × 15 × 3.5 cm Weight: 570 grams Includes: wooden storage case and Dutch-language instruction manual Used vintage condition with visible signs of use and age. The scales show discoloration, while the housing and wooden case show wear. The manual has creases, discoloration and damage along the edges. Please examine all eight photos carefully for the design, details and condition of this particular example. Operation and calculating accuracy have not been verified. Only one example of this product is available. Tracked shipping is calculated separately.

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