The elemenal analysis of the <i>Bonner Klippen</i> is one of the first applications of a method for bulk analysis using x-ray fluorescence excited by high energy projectiles, the PIXE (particle induced x-ray emission) method. The advantages of this bulk analysis especially for archaeometric purposes -- its accuracy and its sensitivity -- are domonstrated as well as its limitations. The analyses are done with the Á8-particle beam of the Bonn University isochronous cyclotron with an energy of 30 MeV. The results of the investigation of the <i>klippen</i> and some coins from the same time are persented. One of the nine <i>klippen</i> analyzed is clearly seen to be a forgery and the authenticity of two more is doubtful. See also AATA-23-2941 for historical background of the <i>klippen</i>.