Mystery box

Device manufacutured by Gould. Tag has the following information:  Model 21-1410-01  S/N 549.  Labels on front:"traverse speed in/sec", "Vernier".  It appears to have some sort of adjustment features.  Very heavy.  I got this lumped in with some DRO displays at an auction.  Free for the cost of shipping if anyone has use for it - otherwise it is going into the scrap metal pile - got to make a run soon to get my $0.035/lb at the scrap yard.  Funny thing is that I would pay them to take my scrap off of my hands.