In particular, item 2-37 begins "Reading a
ferrite-core memory
 destroys the information in the memory." It then goes on to describe
 the restore part of a read operation.  No mention of "core rope" is
 made.  The document, all 200-some pages contains a great deal of
 detail on the computer, including memory operation and organization. 
    What about a magnetic ressonance machine, without the electromagnets?
Couldn't it create a tridimensional map of actual magnetic orientations?