Discovered while cleaning out father-in-law's attic.


The Norden, essentially an analog calculator, could adjust for air density, wind drift, the bombers airspeed and groundspeed while controlling the bombers' final run on the target, thus increasing the accuracy of the dropped bombs. This case held the tangent scales.

The Norden bombsite is featured prominently in Malcolm Gladwell's book 
"The Bomber Mafia: A Dream, a Temptation, and the Longest Night of the Second World War."