Thanks. But in the German original it's not there, which is what got me   
started on this trip. The passage is not quite easy to find, because due to   
the translation a piece of a footnote is lifted into the text. In the   
original it's on pages 136-138. Nowhere does Menger there (or elsewhere in   
this volume) refer to Faktoren der Produktion. He does here (138) write of   
technische Elemente der Produktion. But Elemente are not Faktoren.   
Translations are sometimes misleading.  
  
John Womack