I'm just a novice. So thought that the 2nd screw on each side of the old old outlet was the ground. I can identify the brass and silver, hot and neutral on each side, but there is a 2nd screw on each side. So the installer made an S, having the primary (hot or neutral wrapped nearest the wrapped wire and the very end of the wire forms the second half of the S and terminates under that second screw. I'm really just curious. I know that there is no ground wire. Was going to install a GFIC marked "no grounded" but am even having trouble replacing the circuit box (needed to be deeper for the GFIC, can't seem to get it nailed into the one side stud firmly and square. The back wall in concrete and close to the back of the box - so maybe someone with the correct equipment could attach the box to the concrete. But hey, going to call an electrician now. Good way to spend a Sunday afternoon, figuring out the hassles and complications that electricians face on older homes, etc.