Wall thickness gauge and method utilizing a reed switch and magnet means on opposite sides of the wall

This invention relates to a method and apparatus for determining the thickness of a wall of non-magnetic material. On one side of the wall is positioned a magnetic means adapted to create a magnetic field of which a portion extends beyond the other side of the wall. On the other side of the wall is positioned a detecting means capable of indicating when the strength of at least one directional component of the field reaches a given level at the location of the detecting means. The component on one side of the wall is maintained stationary while the other component is altered in such a way that the strength of the said at least one directional component of the field at the detecting means reaches the given level, at which point the detecting means will indicate same.