Title Page c1923-24
Information in this column is taken from a 28-page pamphlet, "Instructions for Calculating Slide Rules," published by the Frederick Post Co. and printed in Germany.  It carries no date but the addresses listed for city sales room and general offices imply that it was published no earlier than 1922 and no later than 1929.  Since Post published a full catalog in 1922 with rules different from those shown in this pamphlet and another catalog in 1925 with a full line of slide rules completely different from those listed in this pamphlet, I estimate the date as 1923 or 1924.

This pamphlet is the instruction manual that accompanied a Post model 1444 slide rule.  Mostly it is just instructions for using a generic slide rule.  However, it also contains illustrations of  four slide rules identified as models 1442 (5" Pocket Slide Rule), 1444 (Mannheim), 1444A (Rietz), and a 10" "Student" slide rule.  I believe this listing of slide rules supersedes the 1922 Post catalog; these four rules were, in fact, the "Frederick Post" brand slide rules that were being sold in 1923-24. 

I'm not sure who produced the pamphlet.  No source is indicated other than just "Germany."    I have a specimen Post 1444 from this period; it was made by Koch, Huxhold & Hanneman.  I also have a specimen of the 10" Student rule; it's signed "Albert Nestler A.G.  Lahr (Baden) Germany."  I know of no specimens of the other two slide rules listed in the pamphlet.  If I had to guess who produced the pamphlet, I'd pick KHH.