"1443" does not appear on rule itself but black two-piece pasteboard case is marked "Post's Chicago 1443." Back of the rule has USBS Circular 47 and is marked "Albert Nestler A G Lahr (Baden) Germany." Markings are printed on painted softwood.
| This is page 26 of "Instructions for Calculating Slide Rules" published
by the Frederick Post Co and printed in Germany c1923-24. "Post's Student's
Slide Rule" is model 1443.
|
| Post Model 1443, Student's Slide Rule
"1443" does not appear on rule itself but black two-piece pasteboard case is marked "Post's Chicago 1443." Back of the rule has USBS Circular 47 and is marked "Albert Nestler A G Lahr (Baden) Germany." Markings are printed on painted softwood. |