The topic of magnetic compass needles came up on another forum. This led me to get out some cheap compasses and start messing around with them. I lined up three compasses in a north-south row. I expected them to show magnetic north and they pretty much did. I also thought they would do about the same thing in an east-west row. When the compasses were an inch or so apart they didn't affect each other so much, but when I placed them almost touching the needles turned to the northwest. They vibrated about for a bit and when they settled down the outer compasses ended up pointing northwest, but the center compass needle was pointing due west. Why west? Any ideas on this?