I could not yet find out if the mechanism can move in both directions, and if not why not. I have commented on this similarity before. It does not seem to be known whether Leopold had any earlier patterns in mind. Schickard's machine was not one, at least, because Leopold did not know this machine. Obviously there is no direct relation to Schickard, Pascal or Leibniz.
Ma- chines has to go on.
Versuch einer Geschichte der Rechenmaschine, Ansbach 1804, newly edited bv Stephan Weiss, Systhema Vertag, Munich 1992. Li Di, Bai Shangshu, Williams, M. R., Chinese Calculators Made During the Kangxi Reign in the Qing Dynasty, Annals of the History of Computing, Vol. Leopold, J. , Theatrum arithmetico-geometricum, Leipzig 1727, Reprint Hannover 1982. The Use of Napier's Bones in Calculating Instruments, Annals of the History of Computing, Vol. 5, No.