Device for the calculation of conceptional periods and agenesis (Machine-translation by Google Translate, not legally binding)

摘要

A device to determine exactly and by means of a single calculation, the conceptional and agenesis periods of the woman, based on the Rule of Ogino-Knaus, essentially characterized by being formed by two flat discs, metallic or not, superimposed and that They revolve around a common axis, reaching the result that interests according to the days of the month and the various menstrual cycles. (Machine-translation by Google Translate, not legally binding)