10-inch De Luxe Duplex Slide Rule
Frederick Post model 1461 [1936-40]

Hemmi model 153

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 on the q scale.  The usual T scale is graduated in angles and the tangent of those angles is on the C scale.