Dip to the Pole

Magnetize two steel pins so that their points attract each other strongly. Push them into the ends of a piece of foam plastic about as thick as a pencil and balance this by means of a sewing needle over two tumblers (by shifting the pins and pulling off pieces of plastic), if you allow this compass to swing in a north-south direction, it will come to rest with the end facing north sloping downwards. The compass needle comes to rest parallel to the magnetic field lines, which span the earth from pole to pole. This deviation (dip) from the horizontal is 670 in London, 720 in New York. 600 in Los Angeles and at the magnetic poles of the earth 900.