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Post introduced the “Versalog” Slide Rule in 1951 (but it didn’t appear in Post catalogs until 1955.)  In 1969 Post re-arranged the scales and called the revised slide rule “Versalog II.” The earlier version became known as “Versalog I.”  Originally the COS scale on the Versalog I was colored navy blue but starting about 1961 it was colored green.  Some collectors call the rules with navy COS scales “variant Ia” and those with green COS scales “variant Ib.”  This is a variant Ia rule from 1954.
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MARKINGS
TOP EDGE: “CAT. NO. 1460  VERSALOG  FREDERICK POST CO.  HEMMI BAMBOO JAPAN EJ.”  (“EJ” is the date code for October 1954).
FRONT SCALES: LL0, LL/0, K, DF [CF, CIF, CI, C] D, R1, R2, L.
REAR SCALES: LL/1, LL/2, LL/3 [TT Sec T ST, Cos S, C] D, LL3, LL2, LL1.
There is no serial number on this rule; serial numbers on Versalog rules started in October 1956.
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CONSTRUCTION: Celluloid on bamboo.
APPEARS IN POST CATALOGS: 1955-60.  This slide rule was manufactured in Japan by Hemmi but was sold only by Post (in the United States) and Hughes-Owens (Canada).
SCALE LENGTH: 25 cm.
OVERALL DIMENSIONS: 29.5 cm  x 1-3/8 in x 1 cm.
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CASE: Heavy cordovan leather flip-top.  Embossed with Post trademark and “VERSALOG” in gold on front.
BELT LOOP: Cordovan leather embossed with Post trademark in gold.
INSTRUCTIONS (Not shown):  “VERSALOG SLIDE RULE INSTRUCTIONS” Copyright 1951, 5-3/4 x 8-1/4 inches, 115 pp.,  Hardbound.
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CONDITION:
SLIDE RULE: Excellent.  Slight wear, no damage, no graffiti.
CASE AND BELT LOOP: Excellent.  Only the slightest indications of use.  Gold embossing intact.
INSTRUCTIONS: Unread.