Two parallel circular conductors both carry the current in the same direction. The circles lie parallel to the - plane and both have radius . The centers of the circles are at and . According to the cylindrical symmetry the observation points in the - plane can be taken at . Each circular conductor is parametrized by the angle , running from to . The three quantities , , are displayed for the five independent variables , , , , . The observation points are described by , and the source by , , . Units used are in the CGS system