This is the only specimen of a "Ritow Manifold Duplex" slide rule of which I am aware. It was listed only in the 1925 and 1927 Post catalogs.
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The page shown here is from the 1927 catalog. |
| For more information on Herman Ritow and Post "Ritow" slide rules,
click here.
These slide rules were made by Koch, Huxhold & Hanneman in Hamburg. Rules identifed as "adjustable" use the DRGM 192052 friction adjusting mechanism. |