Frederick Post models 1444A and 1444C  [1921-1922]
 
No specimens of models 1444A and 1444C are known. This identical page appears in both the 1921 and 1922 Frederick Post Catalogs.  The selection  of products listed in these catalogs was extremely small; this page lists all the Post brand slide rules.

 
Richardson Direct Reading Slide Rules were featured in the 1921 and 1922 Post Catalogs.   Only the page above lists any Frederick Post brand slide rules.  I attribute the lack of Frederick Post models to the disruption of trade with Germany during WWI. 

The descriptions of models 1444A and 1444C above are identical to the descriptions of models 1444A and 1444C in the 1910 Post catalog.  But in the 1910 catalog these models were specifically identified as A. W. Faber, not Frederick Post, rules.  I haven't been able to find a specimen of model 1444A or 1444C and I don't believe they actually existed--at least not as "Frederick Post" slide rules.  At best they  may have been stock leftover from before WWI marked "A. W. Faber" (not "Frederick Post").   If so, there would be no way to tell if a specimen had once been sold by The Frederick Post Co. 

The "Sectional View Showing Construction" appears to be derived from an illustration in the 1910 Post catalog and 1906-1919 Dennert & Pape catalogs.  I'm sure it was supplied by a German manufacturer but I haven't found the source.