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