[Test-Equipment] Megger Biddle 63220 Earth Tester

[Dave Benham]

I picked one of these up at a ham swap yesterday.  When I  bought it, I
figured I could find a manual online, but I've struck out so far.  It
appears to be a device for measuring ground conductivity or effectivity.
 
Can anyone direct me to a manual, or roughly how to use this device?  
 
It has 5 binding posts across the top of it labeled, C1, P1, Guard, P2 and
C2.  The front face has a centering anolog meter, a 4 position resistance
switch labeled .01, .1, 1 and 10, and 3 0-10 "digital" rotary switches.  On
the side there is a fold out hand crank.  On top and bottom (perhaps the
sides if oriented differently), there are two posts that look like what a
carrying strap might attach to.
 
Any help would be appreciated.  Thanks.
 
Dave  K8TRF