10-inch Universal Duplex Slide Rule
Frederick Post model 1459 [1936-40]
Hughes-Owens model 1766
Hemmi model 152

These pages are from the 1936 (18th Edition) Post Catalog. 

 The T scale is not what one might expect; it gives the tangent of the angle from the q scale.  The usual T scale is graduated in angles and the tangent of those angles is on the C scale.