SLIDE RULE CIPHER DEVICE


 
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This is a rare photograph of a field communications center showing a soldier using a wooden slide rule transposition cipher device.  A number of EE-8 telephones can be seen lashed to the uprights of the truck, as well as a lineman's safety belt and other paraphernalia of field communications. (Photo by Bernard Hoffman. Originally published by Acme and Cleveland Press News, Official Life Magazine Photograph).
 

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This is an enlargement of the slide rule device. (Above text and photos courtesy of  Snyder's Treasures < snyderstr@aol.com> . This item was put up for sale on E-bay).

Stephen A Kallis, Jr. offers some background information. "The generic name for such gadgets is the St. Cyr Slide (or Sliderule).  It's a useful tool for beginning cryptanalysts.  It can be used for polyalphabetic systems such as Vigenere messages as well as for simple substitution".
 
 

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These units were about 8 - 10 inches long, 
and came two-and-a-handbook per set.  The Lawrence units were called "Secret Code Makers," and were popular in the 1930's and 1940's. (Photo courtesy Stephen A Kallis, Jr.)
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The entire device.  (Photo courtesy Stephen A Kallis, Jr.)
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Feb 21/04